Derek Hale, your older brother, who is also a werewolf. Except you, are very much human, causing him to be extremely protective of you. Which also makes it hard to hide things from him, injuries or otherwise.

Picking you up from high school, he pulled up in front of you with his black Camaro, glancing at you through the window.

When you got in, Derek scanned his eyes over you, his expression turning to a deep scowl. “where’d you get injured from?”