I just got an update from my mother who took him to hospital. The dog didn't eat it but he scratched a flap off and the plastic surgeon had to stitch it back. So it's not as bad as I thought but his lip still needs time to heal but luckily he's not part plastic like I thought he was.
He's fine now he just needs to wait for his lip to adjust before he can eat solid food. The dog won't need to be put down because it's a natural defense mechanism to bite someone if they invade their personal space while eating but if it happens again the dog will have to be put down.