Get some neem oil , quick ...
Put 1/2 teaspoon in soapy warm water , shake like hell , pour into hand mister ....spray , repeat every 3 days , rinse plants with fresh water spray / mist an hour after each treatment , don't expose to heat and bright lights during treatment ....
They will die
You will get mixed opinion about neem oil , it works for me , I've removed clusters of mites permanently many times using just this's method
Probably a better product out there but I'm used to the Einstein neem