Barney's Zkittlez Auto ~week 6 - droopy, sad, whitish curly leaf tips?

I would say it's the intense light . I checked your diary and saw you are running your autos 24hrs lights on. Intense light for 24hrs can be a lot for them to take. Remember with photoperiods they only get 12hrs of light , so you are able to increase the intensity . As they get a rest in between. This is called DLI . How much ppfd the plant will get per second. I would suggest turning your lights down a bit if they have grew too close to it. The brown discoloration on the leaves looks like the start of potassium defiency . Which is common as the buds start to form . They will need more potassium in their feed so the buds can swell to their potential. 👍🌱