Instead of cutting, find other healthy ways to release your emotional and mental tension. For example, have a journal to write your feelings in, writing for me has been really beneficial for just letting out stress and emotional buildup. Exercise is another way to get all of the volatile energy out of your system which runs rampant during the teen years. Meditation, eating right, the list goes on and on, the only thing needed to replace bad habits with good habits is time and discipline. And discipline grows the strongest when you're at your most vulnerable but are willing to follow through with it.
Well there are two sides of this I personally believe, one is addiction, the other is stress. I will start by touching on the addiction, I do not know how long you have been doing this or if you have an addiction, but I am merely going to state that after a certain amount of time, people actually begin to grow an addiction towards this and it is very hard to break like any addiction, so if you do have an addiction then you need to treat it like an addiction and make sure you get the right help and support if you do. Next is the stress. You need to find a way to release the stress. I personally would recommend exercise in this case, like doing push-ups or pull-ups or something, or even going out for a nice run or walk. Hanging out with friends and just chilling is a good way to relax. If you feel stressed out by something when doing it, take a couple minute break if you can and just clear your head and maybe do push-ups, go read a book, eat an apple, listen to music or something and then if you need to comeback to it then do but be weary. I do not know if this will help, I hope it does and have a good day!!