If you notice a painful bump on the roof of your mouth, it could be an abscess—an infection that forms when bacteria invade ...

This condition most commonly results in white bumps and patches inside the mouth or on the tongue, but occasionally it can present on the lips or corners of the mouth, as well, Massick says.

Canker sores Canker sores are white lesions inside the mouth ... and painful bumps. They typically occur outside of the mouth on and around the lips, but it is possible for them to occur on ...