It's possible I just dreamed up the most evil superpower imaginable: The Unhealing Touch.
One touch from someone with this power would make any old scar open back up, becoming a fresh wound again (imagine if the victim had survived open-heart surgery). Any broken bone returns to its freshly broken condition; any internal injuries sustained over the course of a life return. At a minimum, their belly button would start bleeding. And it all happens at once.
Come to think of it, I know people with this superpower... if you're talking about emotional wounds.