This study will test the effectiveness of topical thalidomide in healing mouth sores in HIV infected patients. Oral (PO) thalidomide heals these sores at a dose of 200 mg per day. However, PO thalidomide can cause drowsiness, skin rashes, allergic reactions, increased viral load, and even nerve damage that may not be reversible. This study will evaluate the efficacy of a topical formulation of thalidomide (placed directly on the surface of the sore) for the healing of these sores.