SI in all its forms is addicting, that i agree on, in your mind you think it helps coz your transfering mental/emotional pain into the physical which is easier to understand and cope with but in the end its just self defeating and brings on its own problems, how to hide the cuts, how to hide your first aid kit, what excuses you can give for when someone sees, this i know coz i have been there.
its always hard to give up a coping mechanism but this is one you really need to coz it can be a fine line to walk between coping and serious hurt.
everyone is different on giving up, for me i just threw away every blade i had and stopped so i can't advise you on that, you will need to find your own way to do it.
as for help i have no idea what the rules are in the states but in the uk if a therapist thinks you will harm yourself they must,by law, inform the authorities but that doesnt mean you can't get help, you dont even have to mention it, just skirt around it, but you do need to talk to someone, someone that YOU trust and is YOUR choice, but when you do you need to be as honest as you can or feel safe to do so.
its a hard path to walk but with small steps you can do it.