Using a Tamriel_Data head on your player character and adding the "vampire sun damage" spell correctly replaces the head with the generic vampire head. Removing "vampire sun damage" then does not put the original head back, but removes the head body part entirely.

I've only tested this by consoling player->addspell "vampire sun damage" and player->removespell "vampire sun damage" but since the vampirism cure script does essentially that, it's fairly safe to assume using a T_D face, becoming a vampire and then curing yourself via the quest will take your face off.

I suspect there is some hardcoded limitation in the vanilla game that limits the face-revert effect to look only for vanilla faces - or that there is some indexation limit on faces, or whatever.

Luckily, this appears to be a fairly minor bug - once the player equips and then unequips a full-faced helmet, their face returns to normal.

We could consider writing a script that detects the curing of vampirism, adds a dummy helmet to the player's inventory, force-equips it, and removes it, if we want to apply a bandaid fix to this issue.