I know I'll probably get thrashed for this, but personally, I'd chop everything, nuke the room/tents and start over. PM is a Mother F'er to get rid of and yes, like everyone says, it's systemic. I've had mites in veg and used
neem oil to kill em. It took quite a few treatments before I got em all. It really boils down to this (for me at least) I was spending shit tons of time, money, and effort, not to mention the stress on the plants themselves (being stunted) and my own stress of the whole thing. My kid finally pointed out that with the wasted time and not really getting ahead, I could have already had a month or two into a new grow. I cleaned the shit out, cleaned the tents with bleach, H2o2, alcohol, you name it, I used it. Then used an ozone generator (reasonably price around $65 on Amazon) to nuke the entire room, tents, tools, etc. Start fresh - new everything. Also, mites just don't show up. They come from somewhere. If you're working outdoors and then go work on your girls before changing cloths, you can transport mites.