You're confining yourself into thinking that each part needs its own colors.
You can recycle colors as sometimes all you need to convey something is shape, not color.
Doing so will also make your piece look more unified as the palette can breathe through all of your piece.
Do not think in terms of "pants color, skin color" etc. Grass is rarely ever green and the sky is rarely ever blue. Those pants don't need to be blue to appear blue.
You will use less colors more efficiently that way.
You should also always keep the position of the lightsource in the back of your head.
It's not always clear where the light comes from in your piece (the right leg says from the right, head says top right, stomach says bottom right etc).
Oh yeah and the contrast is way cranked up in most colors.
Tone that down a bit and also pay attention that none of your colors are too similar in value if used to as a shading tone of each other.
Turning the picture into grayscale helps seeing that a bit better.