Picture of Erythema Multiforme 3
Erythema multiforme is sometimes associated with the appearance of bulla on the mouth. The lesions should resolve without treatment within about 2 weeks. Viruses such as herpes simplex are often the underlying agent that triggers these lesions. Many medications such as sulfonamides may also cause this condition.
Text Reference: American Osteopathic College of Dermatology: "Erythema Multiforme"