Great work, Thomas! Must be fun to be able to mold the clay the way you want to - but I could imagine that you do miss the Ctrl-Z key! (I do when I get to play with paint sometimes....).
Is this model one big clump of clay? Or do you start with a base from a different material and add then the layers of clay? (Seems otherwise that it would be very, very heavy!).
BTW, nobody has a perfect symmetric face....
Have fun!
Jacqueline