Gargle frequently with a solution made of salt and warm water. the saline mixture sterilises the mouth blisters.
Avoid drinking tea or coffee and spicy foods.
Rub a garlic onto the ulcer. It may sting but the ulcer maybe gone in a while.
Add a teaspoon of honey to a glass of water and gargle.
Mouth ulcers are due to lack of vitamin C. Drink plenty of orange juice.
Much few raw onions as the sulphur in the onions are good cure for ulcers.