Dentists often recommend that teenagers have their wisdom teeth extracted to avoid future problems. However, the medical need for these extractions is unclear at best. Is removing teeth without medical necessity a violation of chavala/chovel b'atzmo? What about in cases where it would definitely improve the patient's dental health, though not save his life?
The Shulchan Aruch (Choshen Mishpat 420:31) rules that you don't have permission to hit yourself, but you are nevertheless patur. This is actually a machlokes rishonim: Tosafos (Shevuos 27a ד"ה אביא) rules that it is permissible while Rambam (Chovel UMazik 5:1) rule sthat it is forbidden.
Since it is a safek sfeika, I would think that it should be allowed to do it. (Safek #1: Maybe the halachah is really like the view that you are allowed to hit yourself. Safek #2: Even if you aren't allowed to hit yourself, maybe you are in this case, because it is possible that there is a medical need to do it.)