It can take many forms. The most common form of self-injury is probably cutting, usually superficially, but sometimes deeply. Women may also burn themselves, punch themselves or hit their bodies against something.
Some people pick their skin or pull out hair.
Self-injury is far more widespread than is generally realised. All sorts of people self-injure. Often they carry on successful careers or look after families and there is little outward sign that there is anything wrong. Self-injury seems to be more common among women, partly because men are more likely to express strong feelings such as anger outwardly. Many women who self-injure believe they are the only person that hurts themselves in this way.