Spider mites! Could also be a nutrient problem, but that looks like serious spider mite damage. I got the little fuckers crawling on my clones for right now. I'm probably going to stick a clone of each strain into quarantine and burn the rest, God rest my little plant's soul's. Do you ever see little webs? You should see little bugs mainly chilling underneath the leaves, and they are small as fuck. It is possible it is aphids, there are species that are red, rather than green. Aphids are easy to get rid of, they are soft bodied, awkward creatures, and don't stand up well to Neem, Azamax, Azatrol, or Dr. Doom. I like Dr.Doom the most if you have a big strong plant. Nothing beat's Doctor Doom, it is some good bug killer that is good up to the day before harvest. I don't think I have ever sprayed something that soon before harvest though.
If you have other plants, discard your clothes, take a shower, and put on fresh clothes, then without getting to close to the infested plant, and without touching it, remove the other plants from the room. Place them in a safe spot where they are not touching each other. In case they have mites as well, you don't want them having a neighborhood block party.
When you have a crazy infestation like that, it's usually best to throw it away. If it's the only plant you have, go ahead and spend 15 bucks on Doctor Doom trying to save it.
