I suggest ditching the dodge and burn tool right now. It teaches you a bit about lighting theory, but it creates bad habits. Probably the worst habit you get from it is relying on it for all shading.
You should look up some tutorials on how to blend colors and painting or drawing in only grayscale colors. You'll learn a lot better techniques that way than with the dodge burn tool.
Another thing i would like to talk about is how light bounces. When you are working with reflective and semi-reflective surfaces, light bounces, especially on metal surfaces because of the hard and smooth face it has.
Btw, light doesn't just hit the edges of the metal, the only effect you are creating with that lighting trick is a thick or bowl shaped metal plate. Smooth out the lighting as well, that's where erasing and color blending would come in handy.