Just wondering if anyone can offer any advice, taking a screen shot with my Samsung S9 edge last night and the colours changed to like a wierd white with blue colour, bit like inverted image but blue and white, ive gone through all the inverted images setting and its defo not one.
Thanks for checking that for me, @Lexie999.
You can also do a hardware test for the back button, select 'Sub Key' from the main test menu.
Press each one individually, the screen will change colour. Does it change for the back button?
Overall, it sounds as though you need your phone inspected by an engineer.
Find your nearest Support Centre HERE.
Clicked on the sub key and it just brings up one screen, blue and that has an exit button in the middle of the screen, i cant get it to change colour at all. I shall hunt for the closest support shop.
Thanks for your help.