Bugs or....?

I can't find any form of bugs on my plants. I'm wondering if it could be mites or maybe something else? I'm going to buy Fox Farm- Don't Bug Me spray. Any inputs would be greatly appreciated. Thanks!

I had the same thing happen to a similar plant of mine.

If you come across any webs or eggs at the back of your leaves then you've either got Spider Mites or Aphids.
They hate humid conditions so spraying just water and maybe some rosemary could help fight those pesky bugs.

But this also could be a nutrition deficiency. Looks like the Leaves need Nitrogen.