I just said a prayer for you and will keep you in my thoughts. I hope you know that even though you slipped up, you have proven to yourself that you can go three months without self-harming. That is quite an accomplishment and since you did it once you can have a lot of faith that you can do it again.
I use other things besides neosporin, so I'm not sure how well it works, but I think it helps protect the wound from bacteria. As far as making scars go away, Bio Oil works really well. I have also heard good things about mederma. I have had very good results with Bio Oil. The length of time depends on the severity of the scar. I have been using it for just a couple months and I have some scars that have almost completely disappeared and others where there is a little difference but it will definitely still be there in a while. It is easy to use -- you can just put a few drops into a bathtub and take a bath, or you can apply it directly to your skin twice a day.