I used to do this too, but I haven’t done it in a long time – well nothing serious. I still give myself the odd (light) slap, but that’s it.
I never planned to stop – never had a goal like ‘I won’t do it for a year’. That’s a lot to live up to. But whenever I got the urge (and whan problems get that bad, it’s a really powerful urge) I’d say ‘I won’t do it now, I’ll do it in a minute/5 minutes/an hour’. Whatever short time period I thought I could handle. And sometimes I would manage, and sometimes I wouldn’t. And sometimes I’d do something less harmful – maybe slap myself once instead of cutting.
Don’t know if any of this is helpful – just wanted to let you know that your goal is possible. And a slip is not a complete failure.

I think for you it might be easier to just take it one day at a t9ime. i know when i was thinking about stopping, i could not say i was going to quit forever. Thats too scary for yourself.

Just say i wont do it for right now, and before you know it your going to be doing so well.

it worked for me and i m only on day 160
something. But it is work in progress, and getting easier.

I hope this works for you!! Good luck, keep us posted!