I agree with eden. Self-harm in any form is valid if it hurts you, no matter how much or how much control you have. Often self-harm starts off as rather 'minor' and with some aspect of control (just to see how it feels / what happens). The problem is that it can become a habit to deal with stress and then even addiction. As you do it more generally you don't get the same feeling so it escalates and becomes more severe.

Is there anyone you can talk to about your depression and how you are feeling? Sometimes just having someone to talk to can make a big difference.