It's pretty obvious that the botox needle has slipped several times, infusing the paralyzing toxin into Nan's brain. Those eyes-wide-open give her an eerie look, something one would find on the Sci-Fi Channel about 2 a.m.
You have to understand, one more face tuck and Nancy will have a goatee...
Remember that cult in San Diego .. the leader of that group had the very same open-eyed stare .. it was eerie!