If a ER Vet is 3 hours away, go, get one on the phone, stop at a fire House /EMT and beg that they can give him a shot of steroids ASAP. Have the vet talk to them. Dogs also have the 'Golden Hour'.
ER Vet, Staten Island, NY - Google Search
Can the pup walk, and are you seeing neuro signs: tripping, feet out of sequence, vomiting, lethargy. Please act quickly.