Canker Sores

Canker sores are ulcerations, small lesions, or swellings inside the oral cavity.

They are different from cold sores—also known as fever blisters—which generally occur on the outside of the mouth.

Canker sores can be painful and are commonly found on the inside of the cheeks, the roof of the mouth, the tongue, or the lining of the lips and may appear white or gray surrounded by redness.

They can often manifest in three forms: