I am not convinced the fever was stress related, however the injury site will most certainly have an increased temp. If your dog's temp was up in general, it is more likely due to a viral interruption that had settled within a certain muscle sector, causing the neck discomfort. This is not uncommon in all mammals. A simple cold can attack any part of our body, seeming to pretend to be something else. I am glad your dog has no symptoms today, but know that a fever is an indication that the white blood cells are fighting something within your k9's body. Keep lots of fluids available for him to drink and a bland diet for another day just in case a more serious condition is lurking below the surface. A quick trip to your vet can determine if the sudden temp increase was caused by a simple 24-hour thing, or if it is a deeper illness that has flared up.
I wish you and your k9 friend the best of health.