This study will last 24 weeks, with a total of 16 visits; screening week 0 (baseline), weeks 1-12, week 16 and week 24. Participants will not be allowed to use any oral or injectable medications for lichen planus during this study. Participants also will not be allowed to use certain creams for lichen planus during the study. The study consists of weekly injections of the medication for 12 weeks and then a 12 week follow up period.