Someng is very wrong with my puppy, please help?

She could have been stung by a bee or a wasp. Or maybe been bitten by a snake. It sounds like an allergic reaction to me also. You can give the puppy some benadryl (dephenhydramine). Usually it comes in a 25mg tablet. That is the correct dose for a dog. But I would strongly suggest you take her to a vet in case there is something more serioulsy wrong. She could stop breathing if she has a strong enough allergic reaction to something. Good luck, I really hop she is ok.