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Updated on August 16, 2022

Can You Pop a Canker Sore?

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Canker Sores: Causes, Symptoms & Where They Develop

Canker sores are otherwise known as aphthous ulcers. A canker sore is a painful and exposed open wound in the mouth.

Although canker sores are uncomfortable, they are often harmless and clear up by themselves. Canker sores are common and can usually be treated at home without visiting your dentist or doctor. 

shocked woman with hand over mouth

While anyone can develop a canker sore, women are more susceptible than men. Aphthous ulcers may also run in families.

It’s possible to have more than one canker sore at a time. They may grow larger or spread in the mouth. Canker sores usually develop on the inside of the cheeks and the lips and tongue.

Canker sores are not cancerous and aren’t the same as cold sores or fever blisters.

Mouth sores develop for various reasons. These include:

  • Genetics
  • Damage to the lining inside the mouth, such as accidentally biting your cheek or tongue
  • Stress and anxiety
  • Hormonal changes
  • Eating spicy foods
  • Eating acidic foods and drinks, such as orange juice and citrus fruits
  • Stopping smoking
  • Having certain medical conditions, such as Behçet’s disease and viral infections
  • Taking specific medications
  • A weakened or overactive immune system

Symptoms of canker sores include:

Severe symptoms of canker sores may also include:

  • Fever
  • Sluggishness
  • Swollen lymph nodes
Canker Sores


Canker sores are open, painful sores in the mouth caused by various genetic factors. They appear as circular lesions and often cause a tingling or burning sensation in the mouth. If you have canker sores that make you feel sluggish, along with a fever and swollen lymph nodes, seek medical attention immediately.

What's Inside a Canker Sore?

Sometimes canker sores are confused with boils.

While the two can sometimes appear similar, they are different.

Boils form from infections that develop in the oil glands or hair follicles on the skin. Often boils start as a sensitive area of the skin that eventually firms. A boil usually contains a pus-filled center that oozes. 

A canker sore is a flat ulcer that has lost the outer coating of tissue. It is not a fluid-filled lump or bump. It may be white, yellow, or gray with a red border. In some cases, a canker sore may ooze with pus. If this happens, the canker sore is likely infected.

Call a healthcare professional or seek immediate medical attention if you are experiencing the following from your canker sore:

  • Increased pain 
  • Swelling
  • Warmth
  • Increased redness
  • Pus drainage
  • Red streaks surrounding the area
  • Crusting 

A fever is also a symptom of infection.

Can You Pop a Canker Sore?

Canker sores are shallow wounds. They are not blisters, boils, or pimples. Canker sores cannot pop as there is nothing to squeeze out.

An attempt at popping a canker sore is likely to be painful.

Do Canker Sores Burst?

Canker sores burst, but not in the same way a pimple may pop. 

When canker sores develop, your mouth may tingle before they appear. Shortly after, a small red bump forms. After a day or so, the bump bursts. A shallow white or yellow open wound is left with a red border.


Canker sores are unlike boils because boils are filled with pus while canker sores are not. Boils appear as bumps and canker sores look flat.

How Can I Get Rid of a Canker Sore Overnight?

There are several home remedies and over-the-counter treatments to speed up the healing process of mouth sores. However, it’s unlikely that any remedy or medication will cure a canker sore overnight.

Many home remedies to treat canker sores aren’t well-researched or studied, so approach with caution. 

Some popular home remedies involve the use of:

  • Alum powder
  • Warm water salt rinse
  • Baking soda rinse
  • Yogurt
  • Honey
  • Coconut oil
  • Milk of magnesia
  • Chamomile compress
  • Echinacea
  • Sage mouthwash
  • DGL mouthwash
  • Apple cider vinegar mouthwash
  • Watermelon frost

Some over-the-counter sore treatments include:

  • Mouthwash containing dexamethasone
  • Topical pastes, creams, gels, or liquids
  • Oral medications

If you have several mouth sores, your doctor may prescribe a mouthwash containing the steroid dexamethasone. This type of mouth rinse helps reduce the pain and inflammation of mouth sores.

Topical over-the-counter and prescription items may help reduce pain and speed up healing when applied to individual canker sores. Topical products for mouth sores often include ingredients like benzocaine, fluocinonide, or hydrogen peroxide.

When mouth ulcers are severe or do not respond to topical products, oral medications may be prescribed. Ibuprofen may reduce pain from canker sores.

Oral steroid medications are also an option. However, they’re often prescribed as a last resort due to the possibility of severe side effects. 

Most canker sores aren’t severe or a cause for concern. Mouth sores rarely prompt any side effects. However, some canker sores may require advice or attention from a doctor.

Speak to your doctor or a healthcare professional if you experience any of the following:

  • A sore bigger than usual
  • Multiple mouth ulcers
  • New sores developing before old ones heal
  • Canker sores that don’t heal after two weeks
  • Mouth ulcers that spread to the lips
  • Significantly painful sores
  • Difficulty eating or drinking
  • Fever


There is no overnight cure for canker sores. However, there are home remedies and OTC treatments for them. Canker sores usually resolve after a few days with proper treatment. If you're experiencing symptoms that are out of the ordinary, get in touch with your doctor.

4 Sources Cited
Last updated on August 16, 2022
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
  1. Canker sore: Care instructions, My Health Alberta, 2019, 
  2. Mouth sores, MedlinePlus, 2020,
  3. Canker sore, MedlinePlus, 2020,
  4. Mouth ulcers, Nidirect Government Services,
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