How to know if my puppies worms are going away?

I got a puppy from the shelter Friday. His belly was swollen so we figured worms and bought some medicine for it. I've went outside with him to go to the bathroom and have noticed no worms. Until today and they were huge. They were also still alive. His medicine is only suppose to last 3 days and we couldn't give him a correct amount because he is so tiny.so I'm worried that the medicine isn't working. Is this normal?

you will have to check his poo. use gloves or a stick to look through it and look for worms.

Has he seen a vet? He needs to go to a vet and be checked out (take a poop sample). The vet can look him over and check his poop to determine what kind of worms/parasites the puppy has. After they've determined that the vet can prescribe the right medicine for him.Without him seeing a vet you're blindly treating the puppy. It's not safe to treat a dog with medicine unless it's been seen and prescribed by a vet. Without going to the vet the puppy could die. This is serious and he needs to go to a vet as soon as possible. Good luck.

ask the vet.