Side mouth sore

A sore on the inside of the cheek or side of the mouth is often trauma or an ulcer, but persistent lesions need examination.

The lesion may be a canker sore, a cheek bite, a sharp tooth edge, a rubbing denture, or irritation from a dental appliance. Its color, border, pain, duration, and location help distinguish local injury from infection or another oral condition.

Rinse with lukewarm salt water, choose soft foods, and avoid tobacco, alcohol, and spicy or acidic foods while it heals. Do not pick the sore, and ask a dentist to smooth a sharp tooth or adjust an appliance if it is rubbing.

Arrange an examination if the sore persists, repeatedly returns, enlarges, feels firm, bleeds, or is accompanied by a neck lump, numbness, fever, or difficulty swallowing. Facial swelling or breathing difficulty needs urgent medical attention.

Ask what type of lesion is most likely and whether a tooth, appliance, medication, or infection is contributing. Ask how long to monitor it and whether a swab, blood test, or biopsy is appropriate.