Board Thread:False Info and Speculative Discussion/@comment-1487677-20160206221007/@comment-4091815-20160206222636

There's a lot to unpack here.

Pain, in the case of Erica specifically, was to trigger her healing ability because, for whatever reason, she wasn't healing after the Kanima attack in the Library.

The healing ability is natural and somewhat automatic to werewolves unless there are special circumstances.

It was implied, though not stated outright, that Peter was so badly injured that it took years to fully heal. The doctor's thought he should be dead so, again, this implies a level of severity. With Issac, the level of severity was again implied. They said that he should have been healing faster but did not until he was conscious and focus on it.

Remember when Derek thought Deaton was the Alpha? He said they could control their healing if they were conscious. We can assume this applied to Peter and his remaing scars.

There are inconsistent elements, Cora's coma was production-induced so she could shoot another show. There are those types of issues as with everuly show but overall werewolf healing is mostly automatic but it's speed can vary significantly.