Getting character lighting values?

I am trying set up a way that I can figure out how much lighting my character is receiving from static/dynamic light sources, so I can assign a damage value every time the character model strays into the light.

I presume because the said character model needs to know how much light is hitting it, and where that light is coming from and that there is a process constantly updating somewhere that I can tap into to get what I need. Only problem is I have no idea where to look?