Canker Sore
Canker sore, a little open wound in the mouth, may cause localization of gum pain. Canker sores are often caused by tissue injury from a toothbrush slip, the sharp side of a corn chip or other hard foods. Canker sores may also occur if you are allergic to something in your food or toothpaste. Some acidic foods or underlying diseases can also cause canker sores. In most cases, they go away on their own after some days. Contact your doctor or dentist immediately if your canker sore doesn’t go away after treatment.