Don't Go (originally by @nadiluvswriting)

Casey has been through so much in the past few years, and the only way she can deal with the pain is by cutting herself. The one person she thought she could confide in, her only friend, has abandoned her, leaving her alone and helpless. When the gorgeous new boy takes an interest in her, will he be able to uncover the mystery of her troubled past? Or will his own secrets tear them apart?
(Credit for the first three chapters and the characters mentioned in them goes to @nadiluvswriting)