Clear bubble on inside of mouth

Minor salivary glands release mucus through tiny ducts into the mouth. Biting the lip or another local injury can rupture a duct so mucus collects beneath the lining, producing a soft dome that may enlarge, shrink, or recur.

Avoid biting, popping, or cutting the bubble, and keep the area clean while observing its size and recurrence. A dentist or oral surgeon can confirm the diagnosis; recurrent lesions are commonly treated by removing the cyst and the associated minor salivary gland tissue so the duct problem is addressed.

Arrange an examination if the bubble remains, repeatedly returns, becomes firm, bleeds, ulcerates, or interferes with eating or speech. Prompt review is appropriate for a rapidly enlarging mass, significant pain, or a lesion on the side or underside of the tongue.

Ask whether the lesion looks like a mucocele, a blood blister, a traumatic fibroma, or another salivary or mucosal condition. Ask whether observation is reasonable, what procedure would prevent recurrence, and whether a specimen would be examined.