@bella7 If someone comes up claiming the puppy, do not return the puppy to them unless they have definitive proof like multiple clear pictures of the pup that have the same little features. I don't trust people not to try to claim pups that are not theirs to either make a quick buck or get a free puppy.
I had this happen to me about 5 weeks ago and I was pretty sure nobody was looking for her considering her condition. Nobody did end up claiming her so she is a happy and crazy part of my family now. Definitely take this pup to the vet and ask for as many tests as you can reasonably afford (fecal smear, blood test, ect.) My stray ended up having two types of worms, an intestinal parasite, parvo, and distemper. But since we tested her and treated her early she survived.
Congratulations on the new family member and I wish them a long healthy life!!!