How did you not find out about this earlier??
This late in the stage will only hurt your grow but your not out of time.
The best thing you can do is to pick up some Neem Oil. Get it from a nursery or where ever, there $13 for the small bottles.
(I believe this stuff is safe for your buds)
So spray your plant down, let it recover, then spray is down with a Iso/water mix at 10% iso to water, again, let the plant recover.
Then spray it down with neem oil, and if you can lower the temps a bit, this will only further encourage the mites to leave.
Wait a few days and spray it down again, by now they should be dead/gone