The bottom will do that when you turn your model into a Sub-d only having a half a head at first. This is because when your in poly mode and want to turn it into a sub-d the last few vertices on the border edge are just loose and move inward when you change it to a sub-d surface. It should smooth out once you attach both sides of the model when your in poly mode then covert it to sub-d again.
It looks like you can still delete a face that is directly under your head, will open up a whole for the neck.
Hope that helps!!!!!!!
Kurt
I am enough of an artist to draw freely upon my imagination, knowledge is limited, imagination encircles the world. (Albert Einstein)
https://www.artstation.com/kurtb
Last edited by Kurt; 20-10-2002 at 05:05 PM.