no pm is POWDER MILDEW, you can try the peroxide mix I’ve personally never tried it, but I use ipm by Athena to help was pm off or this other spray NPK pm wash, o another good one is, zeroton 2.0 by bio safe.
with the peroxide, and water idea you wanna dilute more cause you risk burning everything. with a strong spray. you maybe able to save it. can you post more pics of it so I can better see. I feel you and I don’t want you to lose any herb !!
Powdery moldew is a mold, right ? So you use a mold againts a mold ? Isn’t that too dangerous ?
I am sorry for asking so many questions, I just want to do everything right and understand it 
I am checking the buds everyday, and first thing that appears is the dying little leaves on the bud, and when I look into the bud it’s brown, white, or gray. Everyday I have to get rid of another part of rotten bud 
But I wouldn’t wanted to ruin it just because I have mistaken what it is in the first place,
Just harvest before you have nothing left then dip the the branches- bud in a water and 3% hydrogen peroxide bath then hang to dry the bath will kill any remaining mold
