You have a persistent fever. They may be confused with herpes infections, but unlike herpes, most canker sores are not contagious. They are more frequent in women. They most often appear on inner lips, cheeks, tongue, and throat. It may be difficult to eat or drink the first 2 - 3 days.
Recurrent attacks are common.
See your health care provider if your mouth sores do not heal within two weeks or if you are unable to eat, speak or drink normally. Take Tylenol , ibuprofen or other pain relievers if not allergic.