Canker sores are in the soft parts of your mouth, such as the tongue and cheeks. They are small and shaped like a shallow crater with watery fluid inside. They should go away on their own in 5 to 10 days.
Irritation from acidic foods, such as citrus fruits or vinegar, may cause them. They can come from brushing your teeth too hard. Sometimes eating nuts is the cause. They are not a health problem because they are not from infections, bacteria or a virus.
Cold sores are different. They are usually on the lips or gums. They come from a type of virus that causes genital herpes. Do not use mouthwash as treatment for cold sores. Treatment is with an antiviral cream.
Here is what to do if you have several cold sores. Mix water with baking soda or salt. Or mix antacids and antihistamines. Swirl the mixture in your mouth and then spit it out.
Products such as Anbesol or topical numbing medicines also can be used in small amounts.
Always wash your hands after touching cold sores. If a cold sore lasts more than two weeks, it may be time to see a doctor.
Source: The Wall Street Journal January 28, 2014