Lesions or lumps that appear on your lips or inside your mouth and don't go away are intensely ... pimples on the lip can appear as a fluid-filled bump with a visible head or as a raised, inflamed ...

The result is a small, tender, raised bump on the skin ... When a pimple develops on the lip, it usually appears on the skin surrounding the lip or at the corners of the mouth.

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.