Curling Leaves {look like plastic}

my friend is 6 weeks into his baby girl ak48 marijuana plant and for some reason the leaves are curling and all shiny. Wtf do i do? is this bad? how to fix? any help please. Here's a pic (you cannot tell but the curling leaves are shiny & off color) --

what medium is it?

Slight overwatering will do this

over water imo

looks very pale in colour or is it the light?