I will try and tell my story and I hope it helps some one. I used to SI a lot and had done for 8 or 9 years I cant even remember when I started. I had been trying to give up for 5 of those yrs with no help from anybody else and failing. The good news is I can now say I dont SI any more. Sure I still hit the odd thing when very wound up but havent cut in 9 months. So a few things I learnt from my experience that might help. Never give up you will beat it in the end even if it does take yrs. Tell people close to you. Only once I told other people and took help did I make big changes. The most important thing for me was to always ask God for help when I felt like cutting. Anyway I hope this will help somebody.
Take care
Take care