If the piece is solid colored plastic, you might be able to keep polishing a little more.
The scuffing is basically a bunch of small scratches that you might be able to get through
with more and finer scratches from polishing.
If it is a gel-coated fiberglass panel like a boat,
you may not be able to do that without going all the way through the color coat.
I'd keep polishing,,,, very carefully.
To see what it will look like after you think you're done polishing, run water over the area.
It'll look like it would after you waxed it.
When you're done, wax it anyway.
Polishing compounds, are more or less ultra fine sand paper grit, and don't leave any protection behind.
With out the wax, it will dull out in the sun much sooner.
If it doesn't come out right---- the area might be a good spot for decal/stickers or custom paint stripes.