Original post by: Jonathan Demetrio ,
It could be a problem either with the display outputs on your logic board or it could be a software issue. Did you try to restore an earlier time machine backup? If you don't have time machine, try a fresh install of MacOS. As others suggested It could be the result of liquid damage on the logic board, but you mentioned it only suffered some bumps and drops. Have you opened the bottom of the computer to see if there are any loose connections?