Tristan,
You are correct about the hand not being exposed, however, there is no mention in our rules, whether the hand is exposed or not.
TDA #48 Accidentally Killed/Fouled Hands
Players must protect their own hands at all times. If a dealer kills a hand by mistake, or a hand is fouled, the player will have no redress and is not entitled to a refund of bets. If the player initiated a bet or raise and hasn't been called, the uncalled bet or raise will be returned to the player.
I would never rule the hand be dealt over again.