The Transition by Logan-Ashley Kisner

Seventeen-year-old Hunter, a trans boy recovering at home from top surgery, is mauled by a wild animal in his backyard. His wounds heal unnaturally fast, and he gets his period for the first time since starting testosterone. Convinced it was a werewolf, he and his friends Gabe and Mars set out to hunt it down before he transforms, while Hunter hears the creature's voice, feels drawn to its pack as he seeks revenge on classmates who bully him, and tries to understand his attraction to both of his friends.