
The classic appearance for symptoms of KC to be noticed is between 7-10 days of being infected, so very possible that if this is KC it may have been contracted at your vet's :(
If concerned at all or this goes on much longer I'd recommend you have the vet examine your dog in case of another cause. KC in itself is not a life threatening condition to young healthy animals but can become so if it develops into a secondary infection and is always high risk to very young pups. very elderly dogs and the health of those which is already low due to other medical causes.
Mild coughing or sneezing which is in an otherwise healthy dog can usually be treated by seriously restricting exercise, calming of signs of over excitement, and if necessary a non drowsy cough medicine such as Benolyn or, my recently successful preferred one now, (as appears more pallatable to the dog) Baby Tixylix.
HTH, Teri :)