Hey Michaela, I'm really sorry that your family treats you like that and that you can't seem to resolve it.
As sad as it is, sometimes it can't be resolved. You can't change their hearts, they have to.
Please know that not everyone will backstab you. I know it's hard to trust people, especially when you've been hurt so many times in the past, but trusting is a part of human nature. We're created to have bonds with others and to trust them. Keep your eyes open and see if there is anyone in your close friends, friends, or acquaintance circle that you feel cares about you enough to help you and not hurt you.
Relapsing is indeed a part of the addiction process. But when you relapse, it doesn't mean that all your hard work of not cutting just goes away! I went almost 7 weeks without cutting one time, and when I relapsed, I felt guilty and bad. I felt like I'd lost all my momentum. But it wasn't true. I still had those near 7 weeks that I hadn't cut, and it made me stronger for that period of time.
Try taking it week by week. That's what helped me. Also, having an accountability partner is a great idea as well. You can always find one here on TeenHelp, or even ask a friend. If you don't feel comfortable confiding in a friend, just ask them to "poke" you each week to see how you're doing. You don't need to tell them if you feel uncomfortable about it.
Stay strong. <3