About previous comment, never mind, it's ok.
About flow, I used dotted brushes to the left part and simple - to right.
I think it will be a bit overloaded, though will try to make something.
Also as I understand, light should go like that:
_________________________
|_______________________ /_
|_______________________/_|
|___________-----/_________|
|______________/__________|

That ------ stripe is light from his right hand since it is light source too.
Also will try to blur some parts a little bit more.