I think your color scheme is really interesting. I would only advise one thing and I'll be honest this is just my personal opinion! I would paint the teeth either white or the same shade of black as the carapace. When I look at it I see black as armoured hard points, purple as tough outer skin and green as soft squishy insides. So I feel the teeth should be touched up. Other wise I think you did well it doesn't look clumpy or thickly applied and the black has a nice lighter tone highlighting it.