poorly boy

poor jack has had half of his face pretty much colapse on him. his whole right hand side (left as you look at it) has fallen about an inch and a half. he cannot support his lower lip and is drooling (alot!!) he seems ok in himself but has lost all use of his muscles. he did used to be completely symetrical (as the vet put it) so it is very obvious when you look at it - hard to capture it on camera though!

if anyone has any sugestions i would very much appreciate it. he has no other symptoms (ie signs of a stroke etc), so far the only suggestion that fits is that he has damaged the nerves in his neck - from pulling on his lead - and that has caused it.

thanks for your help in advance!