Inner mouth blister
An inner-mouth blister may come from irritation, an ulcer, or a blocked salivary gland and needs review if persistent.
The short answer
A blister on the inner mouth is often a small ulcer or a fluid-filled lesion caused by friction, biting, irritation, or inflammation. Most short-lived sores improve when the trigger is removed, but persistent or recurrent lesions need assessment.
Which parts of the mouth can develop this type of lesion?
The lining may be the cheek, lip, tongue, palate, or gum. A traumatic ulcer has a raw base; a mucous cyst is usually a soft swelling from a blocked minor salivary gland, while infections and immune conditions can produce multiple sores.
What can you do to soothe an inner-mouth blister?
Avoid biting or rubbing the area, choose soft foods, keep brushing gently, and avoid tobacco and irritating spicy or acidic foods. Do not burst a swelling or apply caustic household substances; a clinician can remove a sharp tooth edge or treat the diagnosed cause.
When should an inner-mouth blister be assessed?
Arrange an examination if the lesion lasts beyond two weeks, repeatedly returns, enlarges, bleeds, feels hard, or is accompanied by a neck lump, fever, or difficulty eating. Seek urgent help for rapidly increasing swelling or trouble breathing or swallowing.
What should you ask about a persistent mouth lesion?
Ask what type of lesion it appears to be, whether a tooth or appliance is traumatising it, and what examination or treatment is needed if it does not heal.
Frequently asked questions
Could this have more than one cause?
The lining may be the cheek, lip, tongue, palate, or gum. A traumatic ulcer has a raw base; a mucous cyst is usually a soft swelling from a blocked minor salivary gland, while infections and immune conditions can produce multiple sores.
What is the first step when you have an inner-mouth blister?
Avoid biting or rubbing the area, choose soft foods, keep brushing gently, and avoid tobacco and irritating spicy or acidic foods. Do not burst a swelling or apply caustic household substances; a clinician can remove a sharp tooth edge or treat the diagnosed cause.
Who wrote this page
This library is published by Dental Nation, a licensed dental group practising in the United Arab Emirates. Pages are written and overseen by the same clinical team that treats patients in our clinics, and are held to a fixed editorial standard for safety and accuracy.
This page is patient education, not medical advice, and cannot replace an examination. Anything urgent — facial swelling, trauma, uncontrolled bleeding or severe pain — needs a dentist or emergency care now.