My golden, Max, had skin problems, constantly scratching, biting and miserable. The vet recommended an ice pack applied to the itchy/hot spot to bring some relief. After testing it was determined that that Max had a very sluggish thyroid gland. Appropriate meds got things back on track, itching stopped, fur grew in thick and lush. I tried elimination diets for the dog and eventually, cooked for him. Seemed to help...and he absolutely loved Cheerios...
. Even after being on thyroid meds, I continued cooking for my dear pooch....wasn't difficult and the vet approved the menu.
Have you considered a thunder shirt? If I understood your post correctly, it sounded like some of this biting may be distress....seeking attention. It is indeed difficult to watch our puppies suffer, I do hope a solution is found soon.