It's a terrible picture, I know.  But doesn't it remind you of a scrunchy face that you've seen recently?  This is known as the "bitter beer face" and when Lois first made that face, it's what first came to my mind.

I was also just reminded by my cousin Camille that I used to make the same face as Lois when I was little.  I think she's right.  I remember my mom saying, "you look so much prettier when you smile."  Needless to say, I went around for days showing all my teeth because - goodness, I was pretty and I was going to show everyone!  I think I'm in for it...