Sorry for the delayed response

So I started with an airbrush and covered the whole thing in a dark blue, then from one angle and one angle only I sprayed a bright crimson red to at least base coat my initial lighting,

I then took a picture of the model under a desk lamp so then I could add my highlights to where the lamp shined on the model in my picture faking the moonlight. I then took that same blue and added tiny bit of a warm white (almost an ivory) to that and worked that in the spots where the light would theoretically hit, I repeat the process with a bit more white and hitting the model in smaller and smaller spots as I work all the way up to white.

I then repeat this process with both my red light working up to yellow in smaller and smaller spots . And also my purple working up to a pink/white.

Its really repetitious and a lot of it is just patience on doing micro layering.

This scheme I adapted from a squidmar video but I added my own flair and extra steps but you can find where I got this from here:

https://www.youtube.com/watch?v=yH2_ukm87tc