Shit. Hard to tell. Hopefully not broad mites! I would hit them with Spinosad or Neem just to make sure it's not a bug problem. Can't hurt. Just don't spray during the day. Pluck all of those dead leaves off before hand. They're not doing any good. If it's not bugs it looks like a plant that dried out and almost died, then got rewatered but took some damage in the process.