Yes please do get your puppy to a vet as soon as you can. She is very vulnerable at 8 weeks old. A puppy who will not eat, or drink and who is vomiting can get dangerously ill very quickly as dehydration is a great danger.
I have no idea what that might be, possibly a reaction to something, possibly an insect bite? That being said, something is wrong and you need to get the puppy to the Vet if this has not improved. Puppies can go downhill very quickly. Please come back to update and good luck.