[Babymax]

Hello
I am a new Yorkshire owner to a 10 week old male. His name is Max, I have had him for almost 2 weeks. I took him to the vet last week for his de-worming and 9 week needle and he was perfectly healthy. He is eating and drinking fine but the past day and a half I have noticed he has been hacking and coughing, once so bad that clear mucus came out of his mouth. He is acting normal but I am worried about the hacking and coughing. I have called the vet and explined his symptoms but they said it could be a dead worm in his lungs, they said to give it a day or so. Anyone have any ideas or experience this? I am worried and I can't wait a couple of days. Thanks