How to get rid of a fever blister in mouth?

Intra-oral or lip?: My patients often use "fever blister" for all ulcers or erosions that occur in the mouth or on the lips. They are different. On the lips are typically herpes simplex virus type 1, treated with oral acyclovir. In the mouth, the ulcer is called aphthous ulcer, which we treat with a topical steroid. Please see your doctor for an evaluation.