A rough white patch on the inner cheek or gum near the lower teeth is often from friction or repeated cheek biting, a sharp tooth, rough filling, or irritation from tobacco. If it is on the tooth surface rather than the cheek/gum, it may instead be plaque or hardened tartar.

Other possibilities include oral thrush, lichen planus, or leukoplakia. A patch that wipes off may be surface debris or thrush; a patch that is rough and does not rub off needs a dental examination. White patches can occur on the gums and inside the cheeks, and persistent ones should be assessed to exclude more serious causes, as described by the NHS leukoplakia guidance.

Seek urgent dental/medical review sooner if there is a red-and-white patch, ulcer, lump, bleeding, increasing pain, numbness, trouble swallowing, neck lump, or unexplained weight loss. These are warning signs listed in NHS mouth-cancer symptoms.

If you can share a clear photo and say how long it has been there, whether it is painful, and whether it rubs off, I can help narrow down the likely cause.

Leukoplakia is a clinical term for a persistent white patch in the mouth that cannot be rubbed or scraped off and cannot be explained by another clear cause, such as thrush or a temporary injury.

It may appear on the gums, inner cheeks, tongue, or floor of the mouth. It is often painless, rough or slightly raised.

Common contributors include:

It is not the same as oral thrush. Thrush often leaves white material that can wipe off, sometimes leaving a red sore surface underneath.

Most leukoplakia does not become cancer, but it is considered a potentially precancerous mouth change, so a dentist or oral specialist should examine any unexplained white patch that persists. They may remove the irritation source, monitor it, or take a small biopsy if needed. The NHS explains the assessment and small cancer risk.

For the rough white area you described: do not assume it is leukoplakia. Cheek biting or rubbing against a lower tooth is common. But if it doesn't clear within 2 weeks, does not rub off, enlarges, has red areas, bleeds, forms an ulcer/lump, or you use tobacco, book a dentist appointment promptly.