my toby had kennel cough and had the dry hacking cough, and then started to cough up phlem when he was getting "better".... he started to do this a week or so before the cough went away.... if it is kennel cough it can last for MONTHS though, i was lucky i only had to deal with it for a relatively short time.... good question though, i dont know if it was a coincidence, but hey im hoping youre lil puppy gets better