soooo tempted to write a smartass answer...but if true, this could be serious - take the dog to a vet asap.
More than likely the lighter will pass without a problem in a day or two. Feed him lots of fiber to get things moving faster.
if it was a zippo lighter , you can send your dog to the factory and they will retrieve the lighter for free :o)<br />
for those taking this question and turning it into a judgment session....F OFF ! get a life.
Offer him a cigar
Don't smoke around or expose dog to an open flame.