Go cautiously with the cutting - I have a badly scarred left arm as a result of self harming with a scalpel in my teens and I've been hiding my left arm for 33 years and I really, really wish I'd never done it. It's been a pain in the ass hiding it all the time. 33 years of not being able to roll up my sleeves or wear short sleeved tops. I still self harm but I use my lower legs as they're much easier to hide than my arms. I also only go quite lightly and I only have very light scarring on my legs, it wouldn't be noticeable unless you were looking for it.
The main thing that helps me avoid self harming is food. I find that 100g of chocolate helps dampen down the urge. Yes I'm overweight but it doesn't bother me much. I used to care about my weight but I don't any more, it's just how I've become as I've got older.
I hope you will try chocolate instead, at least some of the time. I know chocolate is not healthy but it is the lesser of two evils, and chocolate will not leave you permanently disfigured.