Blister inside lip

A blister inside the lip is often a fluid-filled or raw area caused by friction, biting, a blocked minor salivary gland, or an ulcer.

The inner lip contains thin lining tissue and many small salivary glands. A mucocele can form when trauma blocks or injures a gland duct, while a bite injury, hot food, irritation, or an ulcer can produce a tender surface lesion.

Rinse gently with plain water or saline, choose softer foods, and avoid biting, squeezing, or puncturing the area. Check for a sharp tooth, rough filling, or appliance edge that repeatedly rubs the lip.

Arrange an oral examination if the lesion does not heal, keeps returning in the same spot, becomes firm, bleeds, or is joined by fever or spreading swelling. Urgent care is needed if swelling affects swallowing or breathing.

Ask whether the lesion looks like trauma, an ulcer, or a mucocele, whether a sharp tooth is contributing, and what changes would require sampling or treatment.