How do i lighten my rough tan skin ?

Lighten and Smooth: The first thing to do would involve exfoliation to get the dead surface skin cells off and to increase epidermal turnover. Tretinoin or retin a (tretinoin) at appropriate doses is an excellent way to do this. As the skin is exfoliated and "trained" to turn over rapidly it probably will get lighter on its own. If not a medication called hydroquinone can decrease pigmentation in the skin.