Many have this experience. Lesson learned, hopefully. They are probably all in there and you just don’t see them. You can start to spray now, but you’re already going to suffer significant loss.
Next year, you will want to buy concentrated BT (because the stuff you bought is WAY overpriced, and sounds like it has additives). The only way to manage caterpillars is to get ahead of them.
They come EVERY year, and they hit early in flower right as things growing get exciting. Once they start chomping and pooping in your buds, you’re fXcked. You have to cut and trash all the affected parts. The only way to avoid crop destruction is to religiously spray BT according to label.
Next year, buy yourself Monterey BT concentrate before flower starts (it should have directions to mix 4tsp to a gallon, not be ready to spray). Then start spraying by week 3, or about when you start to see little buds form.
IF you mix it correctly, IF your concentrate is not old, and IF you use it early in flower according to label (every 5-7 days), then you will not have this problem again. Don’t forget the shelf life of BT is approximately 2 years. A 3 year old bottle will let you down!! Buy a nice weed sprayer from a home improvement store for application to make your life easier.