This is a book I read around 2010, but is likely to be older. Although I didn't realize it when I read it at first, it was a sequel. I believe it is set in modern day America. The plot revolves around a town that is being taken over by some sort of monsters. From what I can recall, they are basically zombies controlled by a hive mind (a woman from the previous book?).
I have distinct memories of a few scenes, one in which a sleazy character who is "infected" keeps trying to hit on one of the main characters and has to keep eating mints because his breath smells like a dying person's. That guy dies shortly after and becomes a zombie. Another scene is the main characters walking through a forest of some kind where all of these zombies from the town are sleeping, this is closer to the end. I believe the original "evil" originated from some sort of dark hole or swamp, around which wildlife and animals died.
The book ends with the infection spreading throughout the country but this is covered very briefly, just notes of what is taken over and when. Any hints on what this book could be?