Self-harm is most often a physical response to emotional pain. Sometimes we can’t articulate how we feel, we have suffered in some way and we can’t face talking about how we feel, so the only outlet we can find is to deflect from the emotional pain by hurting ourselves physically. Often the physical pain is easier to deal with than the emotional and it can become addictive when we need to not feel the emotional pain.
Self-harm is sometimes done by cutting, burning or pinching ourselves, but there are many other ways to hurt yourself physically e.g. taking illegal and/or prescription drugs, alcohol or using food which can develop into an eating disorder.
It’s really important to ask for help and find someone to talk to who will not judge you or focus solely on the physical injuries. Sometimes, it’s more important to focus on how someone is feeling rather than what they do to themselves. Quite often, people find that more helpful.