My monitor top half is extremely white and colors are washed

Like the title says my desktop monitor's top half became very white and colors are washed any idea how to fix it?

Here is a link for a photo

https://ibb.co/mVoXKT

I used to turn off the screen when I am taking a break from my pc to avoid the heating and let the screen cool down but last time I turned it on this happened , sorry if my english is not very good.