A palette isn't good or bad by itself, it's about the message the palette should convey. One thing to consider is, that you have sculpted your picture (with pixels) with a straight ramp, value-wise. This means, regardless of what colors/hues you use, if you don't want to alter your pixelplacement your lighting is set. So you're free to use whatever color you want and the picture should be readable, at least form-wise. It's all about what you want to convey: Mood, Material,...
Your shading looks a bit like it's a reflective material, like metal. First I tried to make a gold-version. I looked at some references in the internet and tried to reproduce what I saw (in my case
tutanchamun). After I finished the coloring, I checked if the form reads well, by converting all colors to grayscale (looking if I have too similar colors value-wise, too).
Next I wanted to make something more atmospheric, like a mad scientist. There I tried to use some unhealthy colors (checked after finishing by converting the colors to grayscale). And it works too.
Yours works too, form-wise. But I don't know exactly what you want to say, it's not very atmospheric. Imagine some situation your in and look up some reference and change the colors according your feelings to increase the impact on the viewer.
[edit]Here's another version. Maybe a bit more like your initial intention:
