Teen Wolf's Derek Hale no longer has the powers of an Alpha, and the veteran werewolf is now having trouble healing his wounds.

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Derek (Tyler Hoechlin) helped battle the Oni to protect Stiles at the beginning of "De-Void," and he received a slash across his shoulder for his efforts. Instead of quickly healing, the wound remained open for the duration of the episode.

Hoechlin discussed the problem when he dropped by the "De-Void"-related episode of Wolf Watch, attributing his slow recovery to the power differential between himself and the Oni.

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"I think we played with this a little bit before with the mythology of when you get attacked by an Alpha, the wounds take longer to heal," Hoechlin explained. "The Oni are obviously a very strong force, so I think the mythology is that obviously it takes even longer to heal from an attack from them...it raises the stakes a little bit because its not as if something happens to you with one of these Oni you're guaranteed to come back."

However, Scott's (Tyler Posey) torso was skewered by one of the Oni's swords during "Letharia Vulpina" and he didn't seem to have any problems coming back from the wound. While this could be attributed to his status as a True Alpha, it seems like an extremely drastic difference.

Is Derek's slow healing a bigger problem than he is letting on? Previews for the end of the season indicate that Derek will be shot in the stomach, and if he can't heal, Derek could become the major death of season 3B (see video below).

Teen Wolf airs Mondays at 10 p.m. ET on MTV.