I have a tiny yellow dot on the inside of munch mouth where my top lip touches my gum, no idea what it could be, help?

Canker sore: This is most likely a canker sore: a small ulcer, also known as an aphthous ulcer) with a white, yellow or gray center and flat red border. In almost all cases it heals by itself in 7-10 days. The exact cause is not known; genetics may play a role. Fatigue, stress, certain foods affect some people. They are not contagious or precancerous. Numbing ointments or antimicrobial mouthwashes may help.