No, not if he is on a decent puppy chow. All but the cheapest puppy chows are carefully formulated to give the puppy exactly what it needs. None of that stuff is needed, and some of it may domore harm than good. I agree with the dry chow. Canned and moist chows make the owner feel better at the expense of the dog's teeth and jaws that need the exercise and cleaning the dry chow provides. The marketers know how to push all your buttons.
The vet visit is the best thing you can do. They should have given you a record of all the shots and other treatment. Take it too.
There are several things that can be causing the digestive upsets including a sudden switch of chow. Tell the vet all the symptoms and let him decide the best course. It may help to take a stool sample.
I would never advise anybody to buy a 3 month old puppy from a pet store. You risk a poorly bred and poorly socialized dog. You may have a tough time of it. Start at the ''What does a puppy need?'' section of the sticky,
http://www.askmehelpdesk.com/dogs/in...tml#post251802 See also the sections on housebreaking and suggested books.
In addition to heart worm, you may need to add a modern flea remedy. My home is a relatively poor flea habitat, and for years when I only had one healthy young puppy in the house, I did nothing, and they never had any fleas. Three years ago I added an older dog that developed a flea allergy before the good stuff was in wide use. I have used Revolution on both dogs the last 3 years without a sign of a problem.