What can I do instead of self harm?

You can do so, so many other things. My friend once told me to put 'everything' in a corner, and then read a book. Listening to music and maybe drinking some water also helps. And to let out your emotions, choose the closest friend you have and talk about them (your emotions). Maybe have a friend-bonding session, in which you both talk about emotions.

I have learned that writing down whats going on in my life and then ripping it apart really helps me sometimes when I feel like I might do something I would regret, or when I feel overwhelmed.

Instead of self harming you could try writing everything that has upset you or hurt you in a piece of paper and then burn it :)

You can try substituting cutting or burning yourself with another action, such as tapping your fingers against your skin when you feel the urge to hurt yourself, holding ice to your skin, or massaging the part of your skin that you feel the urge to harm. Better yet, you can look for an artistic or athletic outlet to release any pent-up feelings.

Melt an icecube in between your hands. It is painful, but has no lasting scars, effects, or mess. You can easily help yourself out of the sadness of self harm.

What I did when I self harmed to keep myself from doing it was doing all the things that make me happy. Listen to my favorite song, eat my favorite foods. Go somewhere that is peaceful to you. Distractions are the things that will help you to stop completely. I hope that this helps. :)