Get the child serious therapy and provide positive behavior activities. Get them active in team sports that will build true social worth and character. This can make them feel a part of something as a group, less of an individual.
You obviously experienced something traumatic in your early childhood that makes you want to cut yourself. Cutting is an addiction. There's something about yourself that disgusts you, so you cut. You need help to stop. There is no shame in asking for help. You seem like a sweet girl, and you are so young. You have a lot to live for! Whatever your family situation, I encourage you to share your behavior with someone you trust, and ask them for help. You can also call 1-800-DONTCUT (366-8288).
One last thing; music speaks to me and I think to you as well. Listen or download the song "The Way She Feels" by Between the Trees. If you can't download or listen to it, I will send it to you via email.
Hang in there! Life sucks at times, but it's NEVER worth ending.