I don’t know paint.net at all… does it have layers and filters along the lines of gimp?
In photoshop I do almost all my lighting details through the layer effect tools. But my basic idea is to recreate a certain kind of glow I’ve seen in a bunch of photos. The effect is a sharp edged lume layer on top of the hand and a glowing layer underneath. I start by duplicating the hand layer group, apply black at 50% oppacity, then copy the lume fill layer and apply my coloring but no glow. That layer goes on top of the darkened hand, then copy that lume layer, place it under the darkened hand, and either use gaussian blur or outer glow too (if you have it) to get the glow you desire.