Cutting is a very serious issue. It's a difficult topic, as has already been mentioned. If it's any sympathy, when I said in your prayer thread that you are not alone, I meant it...I know the pain...I am a recovering cutter, myself. Cutting stems out of a lot of deeply broken, deeply rooted places in our heart. It shows a physical hurt caused by an even greater emotional pain. A lot of it are lies, maybe you'll understand thoughts like these: "I'm not good enough, I'll never be good enough, I'm not worth anything, I'm hopeless/stupid/f***ed up, things will never get better, I can't change," etc.
Sometimes cutting stems out of a legitimate unmet need, like feeling loved and accepted (sometimes even attention, yes, it's true). Whatever the cause, it's a struggle, and doesn't change overnight to being recovered. That's why counseling, seeking professional help, is suggested to move forward. But it's ultimately your decision as to whether or not you want to get better.
I'm just going to quote this all again for emphasis, as I agree:
Cutters are deeply hurting, broken people. The cutting and self-harm itself is just an indicator and a coping mechanism for deeper emotional issues, like depression or self-loathing. If cutting is something you struggle with, having people tell you you're sending yourself to Hell is NOT going to fix those issues and can only hurt you more. Don't seek people that will treat you that way--seek someone that will help you find professional help, or can at least be there to listen to whatever's hurting you.
Whether it's a sin or not, and whether it means anything to you or not, you're worth something to God. So take care of yourself. Don't smother yourself trying to fight this all alone. Don't get hung up on whether you should be feeling guilty. Seek. Help.
Again, if you have the time, check out
To Write Love On Her Arms' Story (This links directly to the story, and not just the homepage.) They also have a link to various helps, as well, which could prove beneficial to you!
Please know that I know how hard it is to come clean, and I appreciate your willingness to trust this forum with what's going on. My PM box is always open if you need a place to vent or rant... But know we can only be of so much support; we are not professionals equipped in psychology. You're worth more than self-destruction.