There are all kinds of lesions that occur in the mouth. It sounds like yours is an irritation fibroma. The black dot may be where it has been bitten, which is actually a little blood spot. I'd let the dentist lop it off--they'll numb you up with a little shot and you won't feel anything after that. You'll be glad you did. If you're afraid to have it removed just let the dentist keep tabs on it at your bi-annual checkup. You want to make sure it doesn't change, get bigger, or get infected. Good luck.
I had same thing. Except black dot. If they lop it off it can be sent in for biopsy
Mine came back nonspecific. So I could relax it wasn't bad.
I still get them & now have a specialist who burns them off with a laser cooled with water.