mouth problems

In edit mode without subsurf the mouth looks like this.http://home.wanadoo.nl/anton.vandehaterd/download/mouthsub.png

When I click on subsurf the mout looks like this .
http://home.wanadoo.nl/anton.vandehaterd/download/mouthnosub.png

How can I change this right the lips are getting open in the middle?
http://home.wanadoo.nl/anton.vandehaterd/download/mouthsub.blend

do clipping

Thanks that works,
But now this happens with the chin ??
The chin should be nicely round.
http://home.wanadoo.nl/anton.vandehaterd/download/kin.blend

http://home.wanadoo.nl/anton.vandehaterd/download/kin.png

Anton, I’m a newbie … but when I looked at your .blend file … I think I found that the two halves of your face were already joined. Swith off your mirror modifier and you will see that the second half remains. When I switched that off, the bumps on the chin went away.

O thanks that must have happend when I add clipping on
then choose apply and suddenly the modifier mirror disappeared.
So I put a new mirror modifier.

I started to model a new face.
This time I started with the nose instead of the whole face from a cube.
Modelling now with subsurf and mirror modifier on.
Still got a lot to do so lets play blender again.http://home.wanadoo.nl/anton.vandehaterd/download/newface.png

http://home.wanadoo.nl/anton.vandehaterd/download/newmodel.blend