Don't panic. Your vet can do a simple blood test and then you will know for sure. If it is Lyme he will be put on antibiotics for I think it is a month (it's been a while and I am trying to remember). Our vet also uses the Lyme vaccine because he says when the tick bites and latches on it doesn't die immediately but rather has to ingest some of the Frontline first in order to die, so dogs in heavy tick areas need the protection of both the vaccine and the Frontline. Please try not to panic. (Easy for me to say) A visit to the vet will help put your mind at rest.