Sprite Help

[Zemious]

I've been working on this sprite here and need some help with a bit of the shading on the snakes:



I'm not asking for a person to do it for me, but where should I add some shading?
I can't add anymore colors, I can only work with 16 colors and have all of them maxed.

Around the hair (?) If you maek that darker it will look a step closer to realism.

Ah thanks, although I'm going for shading around the snakes.