What Causes Blisters on Lips?

Medically Reviewed on 4/8/2022

What are blisters on lips?

Blisters on the lips can be caused by accidentally biting your lips, burning your lips with a hot surface or food, brushing your teeth too vigorously, or getting infected by a virus.
Blisters on the lips can be caused by accidentally biting your lips, burning your lips with a hot surface or food, brushing your teeth too vigorously, or getting infected by a virus.

Blisters on lips can be caused by many different things and can range from mild to very serious. You can get blisters by accidentally biting your lips, burning your lips with a hot surface or food, brushing your teeth too vigorously, or getting infected by a virus from someone else.

The most common cause of blisters on lips are cold sores, also known as fever blisters. This is a common viral infection that is contracted through close contact, like kissing. They are usually caused by the herpes simplex virus type 1 (HSV-1) and can affect your mouth or genitals. A different strain, the herpes simplex virus type 2 (HSV-2), can also cause cold sores, but it’s not as common.

There is no known cure for cold sores, but there are medicines and treatments that can help reduce the pain and swelling they cause.

Symptoms of blisters on lips

The first sign that you might have a cold sore is feeling a tingling or burning sensation on your lip before you are even able to see anything. A blister will then pop up, usually surrounded by red, sensitive skin. It will ooze a clear liquid before drying up and scabbing over.

Other signs and symptoms may vary depending on a variety of factors, like whether or not this is your first time getting a cold sore. The sores can last from a couple of days to up to two weeks, and they can take two to three weeks to heal completely. Recurrences are likely to appear in the same spot on the lips, but they tend to be less severe than the first outbreak.

Other symptoms that may occur during an initial outbreak include:

Causes of blisters on lips

Cold sores are caused by the herpes simplex virus (HSV) and can spread to the face or genitals through close contact, such as kissing or oral sex. Other activities such as sharing eating utensils, toothbrushes, or razors might also facilitate the spread of HSV.

Cold sores are most contagious while the blisters are oozing because you can contract the virus more easily through contact with infected body fluids. It can also be spread without any noticeable symptoms. Many people who have HSV never develop signs or symptoms.

Once you've had a cold sore caused by HSV, the virus will lie dormant in nerve cells in your skin and may emerge again, usually in the same spot as the first outbreak. Recurrence may be triggered by:

  • Changes in your immune system
  • Fatigue
  • Fever
  • Hormonal changes
  • Prolonged exposure to sunlight or wind
  • Skin injuries
  • Stress
  • Viral infections

When to see a doctor for blisters on lips

Cold sores generally clear up without treatment. However, you should see a doctor if you experience any of the following:

  • Your blisters don't heal after two weeks
  • You have a weakened immune system
  • You feel severe pain
  • You experience irritation in your eyes
  • Your cold sores frequently recur

Diagnosis for blisters on lips

It’s relatively simple for a doctor to diagnose a cold sore with just a visual exam. However, they might swab the infected area to take a sample and have it tested in a laboratory.

Treatments for blisters on lips

Cold sores normally clear up without treatment in about two to four weeks. Several types of prescription antiviral medications can potentially speed up the healing process. Examples include:

Some of these products are taken orally, while others are creams that are applied directly to the infected area.

Other than prescription medication, there are over-the-counter and homeopathic remedies to help fight a cold sore. These can include:

  • Applying a compress. A cold, moist cloth can help reduce redness, remove crusting, and promote healing. A warm compress can also ease the pain of the blisters.
  • Using lip balms and cream. Protect your lips from the elements with a zinc oxide cream or a lip balm with sunblock. If your lips become dry, apply a moisturizing cream.
  • Resting and trying pain relievers. Aspirin or medicine with acetaminophen can assist in relieving fever symptoms or pain if the sore is painful. Creams with lidocaine or benzocaine may offer additional pain relief.
  • Trying other cold sore remedies. Some over-the-counter preparations like the ointment docosanol (Abreva) or another cream that contains a drying agent like alcohol can speed up the healing process.


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What causes blisters on my tongue and how do I get rid of them?

Blisters on the tongue can form due to hot beverages or crunchy foods. They may also be due to something more serious, such as an infection or an imbalance in your body.

The cause of tongue blisters depends on their types. Sometimes, if the tongue blister is not treated on time, it can also infect other parts of the mouth.

Canker sores

Canker sores are a common type of oral infection. They are small lesions that form under the tongue, on the gum, on the tongue, or inside the cheeks. They have a yellow or white center with a red border.

Don't confuse them with cold sores. Canker sores aren't contagious, which means they do not spread from one person to another through contact. You cannot get canker sores from someone by sharing their food or kissing them.

Another difference between canker sores and cold sores is that cold sores always form outside the mouth. Canker sores develop inside the mouth.

Initially, they are painful red bumps or spots but later become blisters. Canker sores are caused due to stress, lack of zinc, folate, and Vitamin B12, lowered immune response, and hormonal problems.

Some people get canker sores at a stressful time in their lives, such as during the exam season.

Mouth injuries, such as biting the inner side of your lip or damaging the lining of the mouth due to brushing too hard, can also cause canker sores.

Sodium lauryl sulfate is an ingredient present in many types of mouthwash and toothpaste. It has also been linked to canker sores.

If you have other symptoms along with your canker sores, such as fever, joint pain, and skin rashes, it's best to speak to a doctor right away.


Oral candidiasis or thrush is a condition in which fungus grows on the lining of your mouth. The fungus that causes this condition is called Candida albicans. Although this fungus is normally present in the mouth, it can cause symptoms of thrush if its growth accelerates.

Oral thrush forms white lesions on your inner cheeks and tongue. Sometimes, it may spread to your tonsils, back of the throat, and gums. It's important to consult a doctor before this happens.

Apart from the fungus, some risk factors can increase your likelihood of getting oral candidiasis.

  • The condition commonly affects older adults and infants due to their weak immunity. Some medical conditions, such as HIV and AIDS, also lower immunity.
  • People with diabetes have a large amount of sugar in their saliva if the blood sugar level is not controlled. This sugar promotes the growth of candida, which can lead to oral thrush.
  • Some medicines, such as corticosteroids and antibiotics, can disturb the natural microorganism balance in the body. This may lead to oral thrush in some cases.

How to get rid of blisters on the tongue

In most cases, blisters on the tongue heal on their own in a few weeks. You can use an over-the-counter pain relief medicine for the pain while you're waiting for the blisters to heal.

If the blisters are due to a fungal infection, your dentist might recommend an antifungal treatment.

How to prevent blisters on the tongue

If you get the right nutrition, keep proper dental hygiene, and lower your stress levels, you can stay safe from tongue blisters. Although these blisters tend to recur, you can lower the frequency by following some tips.

Eat right

If you are getting frequent canker sores, don't eat foods that irritate your mouth. Some examples include pretzels, acidic fruits, nuts, chips, salty foods, and certain spices. If you're allergic or sensitive to any food item, avoid eating it.

Instead, you should eat healthy foods with sufficient vitamins to prevent any deficiency. Make sure you're eating enough whole grains, vegetables, and fruits in your daily diet.

Follow good oral hygiene

Brush your teeth after meals and floss once daily to keep your mouth free of remains of foods that may cause blisters and sores. Don't brush too hard, as that can damage the inner lining of your mouth.

Use a brush with soft bristles instead. Don't use toothpaste or mouthwashes that have sodium lauryl sulfate.

If you have any dental appliances or braces in your mouth, speak to your dentists about getting orthodontic waxes. These will cover the sharp edges, keeping your tongue and inner mouth lining safe from injury.

Lower stress

Often, sores and blisters on the tongue and inside the mouth are due to heightened stress. Lower your stress levels by using different relaxation techniques, such as meditation.

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Medically Reviewed on 4/8/2022
American Academy of Dermatology Association: "Herpes Simplex: Diagnosis and Treatment."

Herpes Viruses Association: "Cold sores questions and answers."

InformedHealth.org: "Cold sores: Overview."

National Health Service: "Cold sores."

World Health Organization: "Herpes simplex virus."

Cleveland Clinic: "Canker Sores."

Kids Health: "Canker Sores."

Mayo Clinic: "Canker sore", "Oral thrush."