Oh hell that's really bad. Swear down, I wish I could tell you something to help you stop doing that, but also understand why it's so bad. I can definitly say your self harm definitly isn't stopping everyone from dying, in fact it's killing you more.
If you mean it like it's an addiction and you can't reeeaaally control when you do it, I guess you can hang around people you like and trust more, since then you're doing something else, that's talking to them, which distracts you from doing any cuttings, and you're not gonna be doing it around others even if you aren't distracted.
Oh yeah, and of course get therapy, like, now, that's someone who does actually know how to help you stop without everything dying and you dying and infinite disorder.