I have a somewhat large dark mark on the inside of my cheek, starting at my wisdom tooth. it almost resembles a bruise. help!

Bruise: It is very likely a bruise--wisdom teeth tend to be "out of line" with the rest of the arch and can cause irritation or accidental trauma. I would have the area looked at by a dentist to rule out other causes.

See oral surgeon: It could be a number of things. Ranging from an "amalgam tattoo", to a "melanotic freckle", to a broken or tangled blood vessel, to a malignant melanoma. See an oral surgeon for exam and discussion of options

See a dentist: Some conditions like dark marks on your cheek may require further assessment; tests and your dentist may schedule a follow-up appointment or refer you to a specialist to determine a diagnosis. See your PCP first.