Don't think about it as "subjecting yourself" to therapy - if you find a good therapist, it's possible to overcome self-injury. Yes, you can do it completely by yourself, but it's much easier with the help of a professional.
There are a lot of books out there on dealing with self injury as well - click on "Ratings" in the bar wayyyyyyyyyyy at the top of the screen, and "Books" and there are a lot of books listed there, some on the topic of self injury which may be useful for you.
We ALL matter and we are ALL important. I'm glad you registered and I hope you find this community useful for you. You do deserve to be happy and healthy.