^Be careful, or you'll burn them, it's really easy, at this point. It's time to transplant, as well, and if you're using decent soil,...time to stop feeding for a week or three,(maybe more) depending on container size. That damaged one will likely recover, I've seen worse survive. They're pretty tough plants.
Also, I can't see the spots, but take a peek at the undersides of the leaves, looking for tiny mites. You might need a magnifying glass, unless you have excellent vision, 'cause they're really small. If you do have mites, I'd scrap them all and start over. It'd be MUCH easier than fighting an infestation, and much wiser than risking harvesting plants full of mites. I hope it's not mites, but, tiny white spots, is a good indicator that they're around.