If your brace is rubbing against your lips and cheeks sometimes ulcers can appear. It is important to cover the trouble areas in wax in order to let them heal. Try to use orthodontic wax, Babybel wax or chewing gum to cover the offending part - dry the area first. To reduce any swelling caused by the brace, use 1 teaspoon of salt in hot water (as hot as you can bare it). Use this solution to rinse your mouth with 3-4 times a day. Simple, but it works!