Self-harm. Teenager about to self-harm using a kitchen knife. Self-harm is any form of physical injury that an individual inflicts upon themselves. It includes cutting (seen here), self-hitting, burning and self-biting. Cutting and burning are the most common forms. Self-harm arises when an individual is experiencing intense emotional distress and can only find relief from their painful emotions by physically injuring themselves. However, the feelings of relief do not last, so the self-harming has to be repeated. Although it can affect anyone at any time, it is most common amongst young women.