as Angelornot pointed out, you are not weak. Cutting is very much an addiction, and addicts of anykind relapse from time to time. When you cut, your body releases endorphins, chemicals that make you feel good. They give a feeling of relief. When I was at the height of my cutting, to get that endorphin high, I cut through skin, fat and muscle all in one deep slash. Every day for four days I did that. Each time filled the bathroom with a huge puddle of blood.

I am worried about you because cutting is a dangerous way to get relief, or the sleep that comes with it. You could cut a tendon or major vessel and ruin your arm for good. Infection too is a big concern. Its not like you shaved your arm, preped it and had on sterile gloves. All it takes is one miscalculation and your life is forever changed.

Running, working out in a gym, walking long distances etc are all productive ways to get an endorphin high. I realize that you primary reason for cutting is not to feel high, it tends to be more of a self flagellation act, but you might feel better there as well by vigorous activity. The next time you have an urge to cut, go running or walking for a good distance, or if you have access to a gym or indoor pool, work out hard.

I would really hate to see you post that you lost the use of your arm.

Sam2