could b start of thrip damage... spider mite damage will show on the top of the leaf before the bottom... lil white spots... thrips do stuff like that.... spinosad ala montery garden insect spray.. call your local box stores; one outa have it... 8-10bux organic thrip killing goodness
oh yeah; the radioshack portable lighted microscopes or just a regular 10x-30x loupe will help u actually see the bugs if they r there for better identification
Is it ok to spray the spinosad during flowering? I usually spray with rosemary oil twice a week and a very very light neem spray once every week and a half or so.