It is a known fact that cutting is very different from a suicide attempt, even though some suicidal people cut. The difference is that cutting is an attempt to change something, to make life a little better, suicide is the last escape.
Someone who cuts, is trying to chance something. We often do not even know what it is. We are trying to get help. If we knew how to make it better, we would. Suicide is the manifestation of the believe, that it is never going to get better and that we are not willing to live like this. Cutting is showing that we do not want to live like this. And that we need help to figure out, what is wrong and get better.