Vampires are not rotting corpse. Whether the time is long past any. Face will also look at blood circulation time. It is nourished by the blood of the victim.
The bodies of vampire isn't generally rotten, no matter how long gone. The face will also show blood flow at all times because of the victim's blood is nourished.
Stoker's corpse will not corruption of time. How long will also see his face at all times with the blood flow of the blood because they have been fed victims.