The person who self-injures may not recognize the connection, but this act usually occurs after an overwhelming or distressing experience and is a result of not having learned how to identify or express difficult feelings in a healthy way...
Self-inflicted violence is a way to express things that cannot be put into words such as displaying anger, shocking others or seeking support and help.
Some people who self-injure have a childhood of emotional abuse. ...they may feel that they deserved it and are now punishing themselves because of self-hatred and low self-esteem.
Expressions of anger were discouraged while growing up
They have co-existing problems with obsessive-compulsive disorder, substance abuse or eating disorders
They lack the necessary skills to express strong emotions in a healthy way
Often times there is a limited social support network