Sores inside the mouth can appear for a number of reasons and are typically found on the inside of cheeks, tongue, lips or gums. Some of the most common causes of these sores are: braces, biting or chewing of the inner lip, a burn from hot food or beverage or chewing tobacco. The best home remedy to treat this problem is to mixing a teaspoon of salt with a glass of warm water and rinsing periodically. This solution will help eliminate bacteria and keep the mouth clean. If the sore continues to bother you, then make an appointment with us and get the best treatment and medication for your sore.