It may be an easy fix, depending on the type of paint that was used. If some laquer based paint was used, thinning it out with some thinner, and then re-painting it would be what I'd do. Either way, personally I'd at least talk to the taxidermists, tell him what you think, and I'm sure he'd offer to change the color.

Look at reference and thecolors won't be that black around the whole eye. There will be some black around the lid, but not the whole eye. Good luck.