I agree that it sounds like oral thrush. This is a yeast overgrowth caused by anti-biotics. Your doc will need to prescribe an anti-fungal medication to cure it. It is important to get rid of it before it spreads to your bloodstream. Mine was dangerously close to this stage, and the first symptom was joint pain, mainly in the knees. It took several rounds of Diflucan to clear it up.