Big battle with Red-faced Nurse

I'm trying to place this fic and I'm having a lot of problems remembering certain details beyond one of the main villains.

The final battle is huge, Buffy and Spike are separated in the battle, and one of the baddies throughout the story is a nurse or poses as a nurse and there's large focus on her face being red or somehow burned up or something like that.

I kept thinking it was a story by The Enemy of Reality or Dampersandspoons, but I think I'm wrong here.

Answering my own query: Clocks of the Long Now by Lostboy