Liquid,

I think that a lot of people who cut do it when they have been hurt by someone they care about or from whom they expected better. I certainly can relate to it. I've felt like maybe they don't understand how much they have hurt me, so I have to make it visable and "show them" (whether or not they will ever see the evidence or hear about it). It can be a way of validating your own pain, by proving to yourself that you hurt, otherwise you wouldn't have an injury.