I had spider mites a while back and tried to cure it as you did. With just about the same results. What I figured happens is that the cure can be worse than the disease if you don't re-rinse the leaves after treating.
I think that the soap or insecticide might be coating the leaves preventing them from functioning as they should. In effect choking the babies. I re-rinsed the leaves, careful not to add too much water to the soil in the process as I didn't want to drown them. I also foliar fed them with a weak (very weak) nute solution. this seemed to help.
Get the hot shot no pest strips from wallmat,lowes,homedepot, as they are very effective at keeping the mites away.

my two cents
Randm999 Reviewed by Randm999 on . trouble with some rooted and unrooted clones in doom HI, I Have a issue with brown spots from the stem to the leafs on my babies, i have had them in the humdity doom from 5 days and some have signs of roots and i had a mite attack inside the doom and on day four i sprayed with Safer insect soap and dip the babies in balance water. Now the plants are drooping bit and i have notice a color of brown from the stem to the top of the leaf. what is the solution to the problem. please i need some answer to take a quick proactive action Rating: 5