"Amanda" (not her real name) was feeling overwhelmed. Her parents were preoccupied with financial worries. Her algebra teacher had assigned tons of homework. And her best friend was not speaking to her because of a fight they had a couple of days ago. Amanda felt alone and afraid. After a particularly tough algebra exam, she felt her world was caving in. she ran into a stall in the girls' bathroom, rolled up her sleeve, and cut her left arm as hard as she could with her nails. She drew blood, but she continued to scratch and cut. In her mind, self-injury was the only way she could deal with all the stress.
A few minutes later, her feelings of hopelessness subsided. While she did not feel happy, she no longer felt trapped. Self-injury gradually became a ritual: every time Amanda was in a stressful or uncomfortable situation, she would "release" the bad feelings by cutting her left arm with her nails or even with a razor blade. She carefully concealed the scars so nobody would ask any questions.
When teens feel sad, distressed, or confused, the emotions might be so extreme that they lead some to harm themselves with self-injury (also called cutting, self-mutilation, or self-harm). Most teens who inflict injury on themselves do so because they are experiencing stress and anxiety, and/or because they were abused as children.
Burning, cutting, scratching, hitting/bruising, biting, picking at skin, and pulling out hair are some of the ways teens use self-injury to cope with intensely bad feelings. Sometimes teens injure themselves regularly, almost as if it were a ceremony. Other times, teens may injure themselves at the spur of the moment, as a way to find an immediate release for built-up tension. Self-injury is an unhealthy and dangerous act and can leave scars, both physically and emotionally.
Stress and Self-Injury
Everybody experiences stress. But stress can feel very different for different people. Sometimes it is characterized by feeling nervous or jumpy. It can also include feelings of intense sadness, frustration, or anger.
These feelings are often (but not always) caused by things that happen during the day (such as a car accident or a fight with a friend). They can also be caused by something that is going to happen in the future (such as a big test or a dance recital). Stress also appears in different levels, or degrees.
Some people naturally feel higher levels of stress than others. For examples, two performers in a school play might feel drastically different about performing. One might be excited; the other might feel dizzy and nauseous.
This difference may be due to a person's biological makeup, or it might be due to a traumatic experience at a very young age. While these feelings may be triggered by a certain event or by many bad things happening in a short period of time, intense feelings of frustration could also be related to a person's upbringing. Children of abusive parents might lack good role models for dealing with stress in a healthy way.
http://www.webmd.com/anxiety-panic/cutting-self-injury