Honestly, I can sympathize with you on the self mutilation, I used to do it whenever I felt depressed.

I did it for years, and it really didn't help manage stress at all, but it was all I knew how to do. I still have scars on my arm because of it. I got so tired of having to wear long sleeved shirts all the time and wearing double layers in gym. I ended up attempting suicide, which landed me in the hospital, where my psychiatrist helped me work through the issues that I had with my coping strategies, and I have not cut in ~3-4 years. I still have issues using x-acto knives and razor blades.
You really just have to get together with your psychiatrist and ask to work with coping strategies for stress. He/she may prompt you to make a Survival list (or he/she may call it something different) where you write down all the alternatives you can think of to hurting yourself, and you post it in a place you see regularly and where you have an urge to hurt yourself. Be careful in your choices of when you cut, if you (heaven forbid) continue, because I know, from experience, that it can be very addictive.

You can beat this, love! If I can, you can. Just try to do EVERYTHING your psychiatrist tells you to do, no matter how stupid it may make you feel. You have to TRUST his/her expertise. That really is the only way to go about beating this. I know you'll be fine, in the end, and I hope you take my advice as I've been down that road, and once you get hooked on that feeling, it's a LONG hard road to get back.
Just know, everyone here loves you dearly.

If you ever need to talk, you know that I'm ready and willing to listen and see if I can help with your problems
PS your picture is TOO cute!
<3 Annie