Hello Ruby!
So I'm not an expert when it comes to that type of lighting, but here's a few tips that came to my mind while looking at your piece.
First, I think you've got the overall idea well set. The character is relatively dark against the bright light, which as far as I know is close to what would happen in real life. However, I think that your edge light (I'm not sure how to actually call it) is probably a bit too bright as it goes away from the center of the explosion. I might be wrong with this but I feel it should somewhat move to darker orange as you move away from the characters head. I made a very quick and rough example to show you what I mean
Also I think that some warm light would probably shine through the thinner parts of the hair making some of the shadowed parts warmer and more saturated. I think it's what is called Subsurface Scattering, but I'm not totally sure about that.
I also took the opportunity to straighten up your character a little as she seemed to be tilted a bit to much to the right. It became more apparent when I flipped the image in Photoshop. You wouldn't want her to fall in this badass pose just because she was off balance 
Beyond that, I think that you mostly need to unify the rendering. The best example would be the skin. Her stomach is very smoothly rendered while her legs and arm have some very visible brush strokes. Same for the hair. Certain parts are rougher while others seemed rendered more carefully. Basically just make sure that the finish level is more consistent. The face and upper body are probably the spots that you should spent the most time as they're the focal point.
As I said this type of lighting is not my strong point, but I hope this helps you. I really like the concept you have going on and it's definitely heading in the right direction. I'm looking forward to see the end result.
