Oliver twitches when Derek takes his hand, suppressing his instinct to pull away entirely. It feels oddly intimate, but then something happens and he watches as Derek's veins pulse a disturbing black color beneath his skin and his arm doesn't hurt anymore.

He shifts his arm a little, can still feel the old bruised skin there, but the immediate pain is completely gone.

"You're just full of surprises," he says, and then adds, grudgingly, "thanks."