It actually looks pretty good to me. You maybe judging yourself a bit harshly - perhaps leave it for a day or two, put it on a shelf and look at it again to see how you feel?
One thing I’ve done in the past is block in the darker colours first (so I guess in this case the entire ‘area’ would be metallic) then edge back in the detail using a detail brush and watered down paint.
But honestly I don’t think this needs that much work!