The plant needs leaves for photosynthesis. I'd leave the leaves on. The light could stand to be a little closer. The spot on one leaf is now big deal. I wouldn't worry about it. I've done that kind of thing by dripping fertilizer on a leaf. The damage won't spread if that's what happened. About the general yellowing on lower leaves, if I have that right, is due to low Nitrogen. Even though you're in flower and almost done, another small dose of fert might be ok. If you're harvesting soon, don't do it cuz you don't want the chemical in your plant. You could just let the plant live out it's life at this point.