when a dog is vomitting over and over again you have to withold water until the vomitting stops or the cycle will keep going the stomach has to rest then you slowly on your finger add water
with such a little one though you have to feel gums if stick and back of neck if skin does not bounce back on a pinch go to er as they can go down fast. I have a 10lb boy and he just went through this vomitting a week ago and it is scary but he is bigger so he can last longer without fluids.
My concern is pancreatitis if vomitting that much
I hope the vet did not give i/d food as that has pork in it and my pancreatitis dog relapsed on that food and sounds to me the combo of food and pepto sent him into a tail spin