You should also check the dog very carefully to see if there are any others. Look between his toes, his ears and every skin fold.
Have your vet put him on a monthly flea/tick preventative (we use SimpleGuard 3, but there are a lot of other good products out there). And have him vaccinated for Lyme Disease. You might also read up on the symptoms of tick-borne illnesses, like Rocky Mountain Spotted Fever.