Looks like powdery mildew try some Azamax it does a pretty good job at mildew and will also take care of bugs. One applicatiom won't do it, you should hit them every seven days with Azamax untill you are about week 4 of flower. Some people won't go past week 2 with Azamax the choice is up to you my friend. How far did you have your lights away from your plants? As rob said those are really stretched. You have to do something to get those tops off the light, I would say LST them but they are so tall not sure that will work for you anymore. If all else fails fuck it grow them to harvest and cook with um and figure out how not to do what you have done here. Dont feel to bad man we all fuck up, if it makes you feel any better not twenty minutes before I replied to your post I leaned down to pick something up in my grow room and managed to run my fat ass into one of my plants breaking one of the branches whoooops there goes fifty bucks worth of bud thank god it was a small branch.