Very small bump in inner cheek (smaller than a pencil eraser), been there over a month, almost feels/looks like a small flap of skin, what is it?

Observe evolution: It looks like you had some type of trauma, which is very common in people. Observe, if it grows fast, see a dentist immediately. Many times it disappears without treatment. If stays longer than a few months, it should be removed and biopsied.

Near 1st molars?: If roughly in line with your first molars, it is likely your parotid duct (drains saliva from parotid gland), and has gotten mildly irritated / enlarged, or could be developing a stone. Continued irritation (frequent checking) makes it persist longer. Can have your dr or dentist examine it of worried.