no-see-do

when a person completely neglects the back of their head when brushing/combing/styling their hair, hasn't washed it for a few days and the back is all cowlick-y at the crown, or is trying to get too much mileage out of a wash and blowout -- the hair looks fine if you're looking head-on, but like crap if you're looking at it from behind.

Sally: Is that a bird's nest on the back of her head?
Betty: No, it's just a no-see-do. She forgot about the half of her head she couldn't see when she looked in the mirror on her way out.

Molly: Whoa, she must have just gotten dropped from a tornado.
Jen: Possibly, but I think she's just rocking a no-see-do. She got her hair done for that event four days ago and thinks she can still work it.