I was brushing my teeth today and noticed a black mark... looks almost like a beauty mark on my cheek inside my mouth.. its circle and I can feel it with my tongue.. any ideas as to what this could be

I would immediately have that checked by a doctor, a dentist if you can't get to a doctor. Oral cancer must be screened out.

It just popped up recently because it wasn't there last week... maybe I bit my cheek or something

I'm puzzled. You were concerned enough to post your question but now seem to explain it away. Biting your check would not result ina round black spot. Do what you need to do.

OK was that you being rude?? I was just asking a question on something I was concerned about... I was just wondering all the possibilities

Yes, you could get a black mark like you described from biting your cheek, if you bite it bad enough you can get a blood blister type raised area. Although, most people will know it if they bit their cheek that badly. It is probably minor, but you could have it checked by a dentist to ease your mind. If they think it to be sinsiter, they will most probably refer you to an oral pathologist.