The dog needs a vet mate, he's dehydrated and malnorurished he wont eat till he's feeling a bit better with himself, the vet will probably put him on a drip of antibiotics and multivitamins 24hrs and he will be a hole lot better, i had the exact same experience with a dog, the culprit was left with egg(or was it blood on his face)? i took him straight to the vets he was in for a week and came out a different dog, dont delay take him in the morning, youve done nothing wrong but the dog needs professional help.