In the pilot study, participants will be randomly assigned to receive thalidomide gel 20mg or placebo (identical gel with no thalidomide) to use 4 times a day for 4 weeks. In the mouthwash study, participants will be randomly assigned to receive 0.1% 20mg thalidomide mouthwash or placebo (identical mouth rinse with no thalidomide) to use 4 times a day for 4 weeks. Participants will undergo the following procedures before beginning experimental treatment, then once a week for 4 weeks, and then approximately 8 weeks after the first visit: