Hi,
I would go back to the vet if that happens and say it hasn't cleared it - and possibly ask about injections instead or possibly even a different anti-biotic?
Did you manage to get all the skin off his nostrils?
I might be totally wrong about this but I seem to recall reading somewhere there isn't as much value in getting a culture done after you have already used a round of treatment?
Anyone know for sure about that?
dr del