Hi. Thanks for your query. Noted the history and understood your concerns. The commonest cause if hard black bump inside the lower lip that sometimes is prominent and sometimes hides can most probably be due to the following reasons: Hemangioma that has got organized. Melanoma should be ruled out. This can be done by: Clinical examination by a General Surgeon. Color doppler studies. And excision with histopathological examination. This will give us the definitive treatment as well as definitive diagnosis to be assured.