Sorry buddy, looks like mites to me....The yellow spotting is a clear indication for spider mites. Not a big drama though as it looks like your still in veg phase. Remove ALL infested leaves first then treat again with pyrethrum if thats your chosen method. Just keep in mind its a contact insecticide, killing only what it comes into contact with, so you have to treat both sides of all leaves plus a light misting of the medium surface. I suggest to remove your plants from the grow room, spray them in your bathtub and give your tent a proper clean with a disinfectant. I personally spray all the edges and corners of my tent with the insecticide as the mites can possibly hide there.
A few notes re pesticides(Although u might know all of that anyway): make sure u swith off all ur fans etc, wear a mask, wash your hands after and make sure ur pets are not around especially cats!!! Whatever spray u use ensure its suitable for edible crops and dont over apply. You can actually kill ur plant by using too much.
If all that is not doing the job write off the grow, bleach the tent multiple times and place it in a cold area for a few weeks (Mites hate the cold) and start again. Once they establish in your grow room they will always come back.....
Not the news u want to hear, i know.....