I'm not too sure who is breeding cannabis plants with genetic modifications to make them immune to pests, so not sure how much of an option that is. BT is what you want. Much easier to get hold of a product with that in it. Specifically, Bacillus thuringiensis kurstaki. It's a bacteria that will kill the caterpillars that try to eat your plant, but it needs to be given to the plant in veg to uptake before flower. It mainly targets caterpillars, so it won't kill any beneficial bugs you might have around. You can read about it more here https://en.wikipedia.org/wiki/Bacillus_thuringiensis_kurstaki Also, do not spray into the hole the caterpillar made, water sitting in a wound of a plant in flower is a recipe for disaster.

Oh no, unfortunately this is rather bad news. You need to cut that out asap. The worm poo and wounds on the plant often causes budrot, but smoking worm shit isn't great anyway. Whatever you lose now will be less than if you wait any longer. Like you saw they like to eat the stem and the whole bud dies, so cut off a little more than you think you need to, to make sure you get all the worms. I have dealt with them a few times and they are a pain in the ass. It's a bit late now, but you can give your plants BT in future. It helps them build up resistance to them.