As much as I hate spraying pesticides in flower I've used
Azamax successfully and have gotten them under control.
@InsaneM
If you don't want to use any chemicals you could take the plant outside and spray it down real good with water to knock off whatever mites you have. Your problem is that the issue is fairly advanced if you're seeing webs so not only do you have active adults in your garden but I'm sure you've got lots of eggs just waiting to hatch. If you had caught it early then I would go with the spray water method but now that you have both born and unborn mites, IMO, you need to go at them with a pesticide if you're going to save this plant.
You won't be able to completely remove them but you will be able to control them to a point that it won't affect the flower.
Now that you have mites in the tent you're going to need to disinfect the tent after you harvest with bleach to kill off any remaining mites or their eggs.
If you go with
Azamax(or Dr.Zimes) I would mix it up at full strength in a spray bottle and wet down the ENTIRE plant from base to tip, under and over leaf, side to side(You get it!). I would repeat this every other day for a week. This should get your infestation under control.
Azamax is used on fruit and vegetable crops. It breaks down within 10 days so as long as your last application is 15 days out from harvest you should be fine. I like to give it a few more days to break down just to be sure hence the 15 days.
You can try what I said and it will probably fix the issue but at the same time you may want to listen to GNick and just start over. Once mites have gotten to the web stage it's tough to get them under control.