It seems that your phone has a screen burn where the display from the application you have used stays on the display. Please perform hadrware test on your phone to determine if it is a problem on the hardware/display.
To do hardware test, please use the phone dialer and dial *#0*# - Please tap the color red, green, blue and black. - Please check if the screen burn are showing on the colors.
If yes, please perform factory data reset. Please backup your phone and remove the Google Account before resetting your phone.
If those steps above does not work, that would be the time where Samsung Engineers need to inspect and repair your device.