It sounds to me like you have mites... I had this problem this year with a new indica I started growing.. since the plant was young when the mites started coming I didn't want to put pesticides on it. So twice everday for about 3 weeks I would go over the entire plant and wipe down the tops and bottoms of the leaves with a soft (silky) rag, and after about one month they were entirely gone. Hope this helps.