Des, have you tried casting your own or another face? The techniquie is pretty easy but does take some time - best not to do your own face on your own.
Basically you put a swim cap on the subject (to protec the hair) and then use vaseline over the face to prevent sticking. Use some pieces of tissue cut to shape and vaselined over the eyes. Allow the subject to breathe either through a straw held in the mouth, or don't cover the nostrils.
Then use mod-rock or similar (basically plaster bandages) cut or torn into strips, dipped into water and layered over the face - smoth them out to get a nice clean finish and ensure that your edges are thick.
Afte the entire face is covered with 2-3 layers you need to let it dry, then carefully price off. Vaseline the inside of the mould (after sealing the mouth or nostril gaps) and place face down in a bucket or bowl of sand to seady it and keep it level. Then pour in plaster of paris or similar and allow to set.
You will probably need to tear the bandage mask to get it off, but they you have a 'flat head to wrok from.