Your screen is fucked
Take it to a repair shop, or if your feeling gutsy
Order a new screen, and take out the old one, and install the new one.
But since you didn't know what the possible problem was, I'm going to assume that you don't know much about computers, and replacing screens in laptops is still an uneasy task for me.
Again, take it to a repair shop, get it replaced, its not the GPU because you said some are flickering, which shows that its still working, but the screen isn't.
(Remember, pick a best answer, even if it isn't mine)