Mouth ulcer inside bottom lip

A mouth ulcer is a break in the mucous membrane, commonly seen as a tender round or oval area with a pale centre and red edge. Appearance alone cannot distinguish every cause, including infection, medication reaction, immune disease, or a lesion that needs specialist assessment.

Avoid picking the sore and reduce contact with spicy, acidic, rough, or very hot foods while it heals. Use a soft toothbrush, keep the area clean, and ask a pharmacist or dentist which pain-relief product fits your age and medical history.

Arrange an examination if the ulcer does not heal, keeps returning, becomes larger, is unusually hard, or is accompanied by a neck lump, numbness, fever, or difficulty eating. Prompt review is especially important for a sore near a sharp tooth that cannot be removed from the cause.

Ask whether a tooth, filling, denture, or habit is rubbing the lip and whether the appearance fits a common ulcer. Ask what treatment relieves pain and what change or time course should trigger reassessment.