Edit: I no longer advocate the use of neem based products at any stage of flower. Bio-accumulation has made me extremely sensitive to azamax/azatrol products. It is _not_ gone in even 60 days of indoor flowering. Please use these methods for veg only.
Complete eradication is still available.
Anything in flower that doesn't have mites on the buds yet... can possibly be controlled. Mix a 5ml/gallon solution of Azamax or Azatrol. Add a Capful of isopropyl alcohol (about 90% or stronger) and a few drops of dish detergent until the solution spreads on the leaf instead of beading up.
Use a sponge and wipe the top and bottom of every fan leaf, not the sugar leaves if possible. Please try not to drip this stuff on any buds. Difficult, but you CAN save your crop.... if you don't have hundreds of plants that is. Wipe the stems and any areas that have mites on them.
Dunk any clones or seedlings in this same mixture and you can also use it to spray.... as in completely drenching the plant but NOT the soil... no isopropyl in the soil please.
Any plants in flower that are 45 days from harvest can have 1ml/gallon put into their res or watered into soilless mixes.... at least 5ml/gallon is good for soil, others have said they can use more without harm... YMMV.
All plants in veg get a soil drench of 5ml/gallon and everything hydro gets 1ml/gallon.
Can you empty your flowering room for 6-8 hours?? Bomb it with floramite if you can.... just not your plants. Scrub down the floors and walls with a 5-10% bleach solution.
Spray/Dunk plants in veg every 5-6 days for 2-3 weeks... that should break the cycle. Keep them dosed with soil drench or straight in the res every 30 days.
You CAN get rid of them and the preventative maint in the veg room will keep them out. No need to rip everything down.