Palette reduction, I need help

[golbez22]

Hey I have been trying to bring my color count down as far a possible lately, and I have been mostly successful and have brought the count below 16 in most pieces...but a particular piece I need help with...I want to reduce the redundantly similar colors without losing detail.


here is my current palette:


and here is the image it belongs to:


not much else to add except that I think there needs to be more contrast in the piece to match my other pieces better:

they have 13 colors fyi