Tamara had an amputee fetish. That wasn't a problem in the 23rd century. You could regrow an arm or a leg from a cloning tank. There were "do-it-yourself" kits for that.
At school she would show up completely normal in the morning. But after a few hours she could barely sit still. Once the urge became too great she'd cut small things. A toe, a finger.
Once the other students found out, they started teasing her about it: "Cone on, let us cut you. Only a little bit."
She really shouldn't have given in to that. They made a mess.