Why did my screen completely blacked out and became unresponsive?

I have a Samsung Galaxy A7 (2016) which was facing a screen flickering problem. The next time it fell off, my screen became unresponsive and gradually blacked out.

In order to be more specific, first the screen turned into a violet colour gradually (starting from the top) and then completely blacked out. Though the screen is unresponsive but the home key and the volume keys still work. Also I can hear the sound of messages and answer calls with the home key. So i guess my phone is still working.

Will replacing the screen solve the problem? or are there cheaper solutions?

please help asap!!