What is the best way to take care of mouth ulcers/canker sores?

Many types? : There are different kinds of mouth ulcers, traumatic, aphthous, and some related to medical conditions. The type and cause determines the best treatment. Two options: one- get some orabase to cover or orajel to numb the area since we don't know what you have or two- see a dentist who can diagnose it and then give you the best advice.

Canker Sores: are the most common oral lesions. Individual ulcers typically last 1-2 weeks. The cause is not known. The aphthous ulcers are usually self-limiting. Try to keep adequate oral hygiene as possible. If concerned see your dentist for exam.