If you look for bugs, check underside of leaves, and the stem of the leaf. Check both the rough looking leaves and the good looking leaves, sometimes they’re hard to see/find. Sometimes you’ll still be able to see them without a scope or a loupe.
Also be careful of spraying anything on them while the lights are on them, they’ll burn/damage faster/easier. N try not to do too many things at once or any drastic actions. Sometimes we do more harm than good trying many different things and we never actually figure out what “fixed” it or what the actual issue was.
Damaged leaves don’t really ever get repaired, some do to a point, but keep looking for new growth to see if the problem is getting better. Happy growing n I hope you are able to get it under control. Best of luck to ya 