Tell me how do you get rid of a mouth ulcer?

Canker sore cocktail: Rinse for 10 seconds with an equal mixture of maalox stomach medicine, liquid benadryl, (diphenhydramine) and chloroseptic sore throat medicine. Then rub orajel on the sore. Next place a small amount of salt on your finger and hold it against the sore for ten seconds. Repeat 3-4 times a day. If you are prone to canker sores, your dentist or doctor can prescribe an anti-viral.

Time: Most oral ulcers will heal in 10-14 days no matter what they were caused by. They are most painful in the first 5 days and after that they start to feel better.

Gargle and avoid...: Since you mouth is teeming with bacteria, and the sore is the result of a herpes reactivation to due the virus perceiving stress: 1. Reduce the bruden of bacteria near the wound by gargling with listerine or salt water 60seconds twice a day until the sores go away (the bacterial load near the sore may delay healing), and 2. Avoid sour, citrus, acidic, spicey foods which will irritate the sore.

Depends: Without seeing the ulcer i can't really help. It could be anything from a cheek bite to cancer. If it isn't going away (within 7-10 days) or is larger than a pencil eraser then i would recommend being seen by a dentist.