Maybe you've just gotten braces . There's one guy at school, though, who takes the teasing to a different level. Taunting or teasing like that is a form of bullying. Maybe you're Asian-American or you like to write poetry. What they share is the power to upset or hurt the people who are being targeted.
Bullying can be physical, too.
Maybe each time this guy sees you in the hall he intentionally walks into you and then blames you for being in his way. Or you might accidentally knock your books off your desk, only to have him accuse you of trying to trip him. It can be really scary. For specific medical advice, diagnoses, and treatment, consult your doctor.