Mouth Sore Won't Heal? Talk to a Dentist Online

Canker Sores (Aphthous Ulcers)

Small, shallow sores with a white or yellow center and red border, usually triggered by stress, minor injury, or certain foods. Heal within one to two weeks.

Cold Sores

Caused by the herpes simplex virus, typically appearing on or around the lips rather than inside the mouth, often preceded by tingling.

Oral Thrush

A fungal infection causing creamy white patches, more common in infants, denture wearers, and people with weakened immune systems.

Leukoplakia

White patches are often linked to tobacco use or chronic irritation; they are usually harmless but should be monitored.

Irritation from Braces, Dentures, or Biting

Repeated friction or trauma can cause localized sores that heal once the irritation stops.

Oral Cancer

A sore, red or white patch, or lump that doesn't heal within two to three weeks, especially with no clear cause, should always be evaluated.

Level

What it looks/feels like

What it usually means

Mild

Small sore, mild discomfort, improving within a week

Likely a canker sore or minor irritation

Moderate

Sore or patch lasting one to two weeks, some pain, may recur

Could be recurrent canker sores, thrush, or ongoing irritation

Severe

Sore, red, or white patch persisting beyond two to three weeks, growing, or painless but changing

Needs prompt evaluation to rule out a more serious cause

How to Manage Mouth Sores at Home

Rinse with warm salt water several times a day.
Avoid spicy, acidic, or rough-textured foods that irritate the area.
Use an over-the-counter oral gel for temporary pain relief.
Identify and remove sources of friction, like a sharp tooth edge, braces wire, or an ill-fitting denture.
Keep up good oral hygiene with a soft-bristle brush to avoid further irritation.
Manage stress, a common trigger for recurrent canker sores.

Talk to a Dentist

When to See a Dentist About a Mouth Sore

The sore or patch hasn't healed within two to three weeks
It's growing, changing color, or bleeding
You have multiple sores at once or they keep recurring
It's painless but persistent — this still warrants a look
You have risk factors like tobacco or alcohol use

See a doctor promptly if a sore is accompanied by fever, difficulty swallowing, or signs of a widespread infection.

Talk to a Dentist

When to See a Dentist About a Mouth Sore

If it lasts longer than two weeks, keeps coming back, or is growing in size, it should be evaluated by a dentist.

White patches can result from irritation, oral thrush, or in rarer cases, precancerous changes — all reasons to get it checked.

No, canker sores are not contagious, unlike cold sores, which are caused by a virus.

Most canker sores and minor irritation-related sores heal within one to two weeks. Anything lasting longer than two to three weeks should be evaluated.

Not always — many white patches are caused by minor irritation or are harmless. But a patch that doesn't wipe away, keeps growing, or persists beyond a couple of weeks should be checked.

Canker sores appear inside the mouth and aren't contagious. Cold sores are caused by a virus, typically appear on or around the lips, and are contagious.

Yes, stress is one of the most common triggers for recurrent canker sores, along with minor injury, certain foods, and hormonal changes.

Yes. A licensed dentist can review a photo or live video of the area, ask about your symptoms and history, and recommend next steps — including whether an in-person exam is needed.