My 3 Year Old Son Had A Fever Monday And

My 3 year old son had a fever monday and tuesday (yesterday) and today complains that his stomach hurts and has a large white colored sore on the side of his tongue. He did vomit earlier today, however, I am not sure if he just ate some applesauce too quickly or not. I do not see any sores on his hands or feet at this time. thanks for your help