VIL's mask has 2 sides to it, the normal basic Plague mask side which people saw often during the plague and then the other side being white with black accents, to symbolize a skull forming under the mask after the mask starts to decay away. (U could see the skull side in the submission VIL the Collector).

I thought the idea of him having a 2 face style mask was cool to kinda show the different sides people saw him as. The normal black plague mask that could be off putting for most people already, but sometimes it was also a sign of hope for those in desperate need. Then the skull side to signify death and the horror that the plague was. Also a sign of VIL's own demise in the last week of his life with his flesh rotten away.