I have like a sore in my mouth upper cheek its white i had no pain until i start messing with it.i prick it and it bled now today i wake up with paint when i eat on my right side it hurt .wat is it.

Sore : Based on the description it is hard to tell what it is. But i recommend that you be seen by dentist or at least a primary care physician to make impression of what you have and then refer you to specialist. If you incidentally bit your lip or burned it, it may be due to injury but without having more history and physical exam, it's hard to make correct impression.

Oral white patch: The white patch in your mouth may be leukoplakia, if it did not come out easily. The other possibility is oral thrush where multiple patches on red base with pain on swallowing. Pricking with bleeding increases the chance of infection. Good, you are on cephalaxin. Do you chew or smoke tobacco?Leukoplakia comes with tobacco. Precancerous! see your dentist & check it out. Welcome to healthtap.

Don't know, but: It is hard to say what the white patch was and if you caused the pain by messing with it or not. First, stop playing with it and give it time to heal. Second, see a dentist if it does not heal, pain is getting worse, or if you are concerned about this spot.