I think there is a lot of wonderful information online for depression self-help and also for self harm self-help. Find some websites you feel might be helpful for you and put what you learn into practice in your daily life. Take it one day at the time, but do the work.
As far as your friend is concerned, if you feel you need support then tell her you're just asking for support and want someone to listen. She either will, or she wont
Recovery is like everything else -- it takes effort to make positive changes. This may not seem like a good example to you but say you want a new car.... you can't just go out and get one overnight. Youd have to work to save money to get the car for a good long while. It's not easy, but many of us have done it. It's the same with everything in life, and believe me, you can do this!! If i could, YOU can too.
Self-help can be much more beneficial than professional help, because it's something readily available to you every day online. A therapist is someone we only see once every week or two.
i hope you'll look into the self-help and make it a long-term habit. Not for a day or a month, but in the long-term
take care of YOU.... and stop following this self-harm fad. That's what it is, a fad. You're wrecking your beautiful skin and not taking care of your emotional health.