Ok time for class to begin , Powdery Mildew is commonly attacked by organic gardeners with milk , yes milk but most prefer Non pasteurized farm milk as it is more natural . The milk needs sunshine to be most effective and I do not recommend doing this to an indoor grow .
The peroxide shit Cervantes came up with is not fool proof and in the end I still would not touch that bud , even with a bath and rinse in peroxide solution . The spores are all over your grow and beefing up the fans now will only make things worse than they already are . Sad to say as mentioned it is the end of the road for these rowdy teens and you will adopt more in time , crops are thrown out everyday . I toss more bud every year than most people can smoke due to Bud rot and the mold it harbors . Heavy yielders tend to have this downfall !
In your case it is cool temps and high humidity along with a lack of proper air circulation that brought it on in the first place , Pm thrives when there is a drastic temp swing and actually is more predominant with cooler temps .