Prescription med. There are several meds for this condition, but not available otc. Should have it checked to make sure that is what you have first...If it is confirmed thrush, I am sure you will be treated accordingly. You should also inquire about why you got thrush. Good luck.
See your doctor. There are some rather easy effective treatments, however most importantly you must figure out why you have thrush. Thrush typically only appears in infants that have an incompletely developed immune system or in adults that are immunocompromised.