Are you confusing herpes with mouth Ulcers....? Uclers usually are inside the mouth on the insides of your cheeks and gum line, they are white and very painful. Herpes usually will appear on the outside of the lips or corners and start out as a small pimple or clear fluid like blister and then turn into a sore..( you will usually experience some burning and tingling, prior to the OB).. If you are unsure, ,my best advice would be to go to the doctor and ask to be checked out. If he/she thinks there is a possiblity then they can test you to be sure.. I wish you the best...