This is a really difficult question given the fact that system in systemic mastocytosis such a rare condition, and there simply is not going to be a lot of resources that can tell you if it is completely safe or not. If I were to inject you, I would call Allergan (the makers of Botox) and ask for input from their clinical physician team as they would have the most up to date data bank on complications and/or safety with this condition. It takes a little bit of time to hear back from them, but they will get back to your provider with an answer. All in all, Botox for cosmetic purposes is an ELECTIVE procedure, and not a life saving procedure. You would not want to proceed with it unless completely safe. That being said, best of luck with this difficult issue. Best, Dr. Giordano