Goes through cycles where her roommate is her best friend and then her worst enemy. Cassie sometimes feels so alone and unsure of herself that she purposefully cuts her own body. Cassie may suffer from

Self-injury

Explanation:

Self-injury usually occurs when people face what seem like overwhelming or distressing feelings. It can also be an act of rebellion and/or rejection of parents' values and a way of individualizing oneself. Sufferers may feel that self-injury is a way of: Temporarily relieving intense feelings, pressure, or anxiety, Being a means to control and manage pain - unlike the pain experienced through physical or sexual abuse or trauma., Providing a way to break through emotional numbness (the self-anesthesia that allows someone to cut without feeling pain), Asking for help in an indirect way or drawing attention to the need for help, Attempting to affect others by manipulating them, trying to make them care, trying to make them feel guilty, or trying to make them go away

Self-injury also may be a reflection of a person's self-hatred. Some self-injurers are punishing themselves for having strong feelings that they were usually not allowed to express as children. They also may be punishing themselves for somehow being bad and undeserving. These feelings are an outgrowth of abuse and a belief that the abuse was deserved.

dude you should crop your image so only the question shows. but   can you explain it better