MacBook Pro screen is faded white

My MacBook is about 4 years old and suddenly the screen looks washed out/faded. I have chatted with the apple store and have done a few resets, including safe mode but nothing has changed. They were not very helpful. and were unsure how to solve the problem. I have always had a MacBook and never came across to any issues except for this one. It is currently updated to IOS 12.1. It has never been dropped, taken outside or water has been spilled. I am thinking it is a chip or something to do with the LCD Screen. I have no idea how much that would cost to fix. Any ideas or suggestions? many thanks