Well, whoever does that probably has a death wish, Tev keeps it tucked in in combat and is usually wearing a helm, so they’d have to go for it specifically, which means that he’d make sure they’re extra dead.

The way I figure blood regeneration works is that it restores him to the state he was when he was raised so eventually after he killed enough things his hair would end up the way it was. That’d probably be one of the last things restored so he’d look a bit lop-sided until the magic finished its work.