Is this a mite?

Yes sir looks like some webbing just starting as well. If your close to chop, not a huge deal. I would recommend wet trimming and possibly washing off before hang drying if your concerned with bugs in final product. If you can keep your drying room below 40% RH than washing off wet trimmed nuggets isnt a huge deal as far as mold and mildew. If you cant get drying room below 45%RH than i do not recommend washing off final product before hanging. Hope all goes well for ya

 

The only thing I've sprayed, and would even suggest spraying that late, is kombucha and LABS/EM-1. Those wont necessarily take care of your mites but the kombucha really slows them down, I think the acetic acid in it is very irritating to them. And washing your colas in buckets of water before hanging is also an option like lovinthegreentrees said, I've done it before in my friends garden that was super dusty and got a lot of dirt off those nugs.