The first thing you should do if you think your plants may have a copper deficiency is to flush out everything with pH-balanced water that contain a mixture of nutrients. The pH level is extremely important. If your growing marijuana in soil, copper will be absorbed by your plant the best if it is at a pH level of between 6.0 and 7.0.
Just to add some to Croatsan's answer
Try to find a product to add copper and I think foliar feeding is the fastest way here make a tea of it and spray). Since you are so close to the end.
Copper problems makes buds smaller...
Don't take my guess for granted. It's just that - a guess. Why don't you wait a bit and see if some of the members more experienced in these matters chime in and maybe come up with something else.
I would just wash my hands every time I go in the garden don't smoke. There really is no cure. It's really not going to kill your plant just make it look ugly and the yield will be lower
I'm not really sure if this works but I've been doing it for a long time now. I feed my plants raw milk and molasses to build their immunity. I'm not sure if it works but I haven't had tobacco mosaic virus in a long time