Samsung S9 mark on Screen

killie77

Hi
Have an S9 which has a Mark.Doesnt seem to be a Scratch more like a drop paint or similar. I've tried a couple of drops of acetone left it for ten fifteen minutes tried to remove with a plastic scraper.still their
I'm going to Pist a pic of the Mark it shows up better on a white background. Would love to know how to remove it without damaging the screen.
As I'd like to put it up for Sale
Thanks
Ian.