Hate to say it, but unless you’re spraying in July and August you’re pretty much SOL at this point. The mouths lay the eggs on the cola tops, when the moth hatches it’s super tiny and moves towards the center of the bud where it sets up shop, munching, pooping and growing along with the bud. By now your buds are going to be fairly big (hopefully) and the worm is deep inside. When you spray late in the season, it’s real hard for the Bt to get inside the bud where the worm is. (The worm has to eat vegetation with the spray on it, the spray will not kill the worm on contact.
It’s not like spraying is completely unless (It will get any new worms that are just hatching), but not nearly as effective as spraying in the earlier months when the spray covers all the vegetation. If you live in an area where the worms are a problem, you should start spraying before you ever see them.
At this point (depending on the size of your crop) you should do as much manual inspection as possible, concentrating on your top colas. (You will hardly ever find them down low deep in your plant. They’ll primarily be in your top/highest colas.) When you find them you’ll almost assuredly have to remove a portion of the bud. But if you don’t get em out, the entire cola will end up rotten due to all the poop and dead vegetation in the center,