Since you are a medical professional, i believe in your diagnosis pf flat warts. The easiest option is to undergo a touch cryotherapy which should treat the wart without any complications. Preparations of salicylic acid exist but they can cause hypopigmentation on prolonged usage and so is true for some other medications. Mechanical removal by electrofulguration is another good option. High doses of zinc after removal of warts are suppose to be helpful in preventing a relapse.