Two years old seed

I thought I had it under control. I was sooo wrong. It might have been the hottest summer in our history, the dry air (RH constantly under 30°), my newbie mistakes (of course). I don't know, but the results are here. Overnight, a slight presence of little white critters became an infestation. A big one. Ladies and gentlemen, I give you the mighty bloody spider mites in all their furious glory. Not much to do about it, I'm afraid. We are at the very end of flowering, so in a couple of days I'll axe it anyway (flushed already, a week ago). And I can't, of course, spray it with pesticide or soap or oil or any other product. The plant is clearly suffering. It doesn't smell at all. Sugar leaves are browning, and on their surface there's no sugar. It looks like a total disaster. I'll try to wash the buds, right after harvest and before drying. But I really don't know if it will help. This one might end in the trashcan.