Damn I'm so sorry to hear about that teacher who used to bully you....Did you report him/her to the principle? That is despicable behavior from a teacher and they deserve to be fired. You should talk to a psychologist as to why you feel the need to hurt yourself when you stutter. To me it sounds like you blame yourself for your stutter, and you're angry at yourself for that. It's actually not your fault. Forgiving yourself for stuttering is the first step to overcome it.