The Mark of the Wolf by JS Groves

When a Margaret is attacked by what she believes to be a werewolf, her life is turned upside down. Confused and afraid, the only people she feels safe going to for help are the strange goth kids that everyone says are witches. Dominic and Aaron are Pagans, not fools, and smell a trap. But Jacob insists they take her seriously. When they agree to help her, they - and all their friends - are swiftly drawn into a larger world of monsters and magic more dangerous than they had ever suspected was real.