Im assuming there isn't drop damage, so this feels like you might be dealing with OLED bleeding :P
[image|3057510]
does the patch look like this?
so you should probably just replace your screen, as there no real way to "reverse" OLED bleed.
[link|https://www.amazon.com/Digitizer-Replacement-Samsung-Galaxy-M10/dp/B08GBVLN5Y|Amazon.com: Display Touch Digitizer Glass LCD Screen Replacement for Samsung Galaxy M10 Black SM-M105F SM-M105G SM-M105Y SM-M105M : Cell Phones & Accessories|new_window=true]