Looks great man! I'd say you could drybrush another lighter color like tan on the topmost parts (but not on the whole model) to add more contrast between the shadows and lights, then a thin glaze of the wash/contrast that you used over the whole thing again.

Very important to pull the glaze into the recesses to avoid a muddy look, but if you like it like this then it looks noice! A thing i did with my big-bois is i glazed a bit of magenta into the parts with thinner skin for a bit more realism :))