A part of the screen changes its color and flashing in the background

Hello,

my husband accidentally dropped my macbook pro 13 late 2013 on the ground, and the screen is partially changed the color (like show in the picture), the problem doesn’t show up when I connected to external monitor. The computer is working perfectly fine except this problem. I don’t know if I need to change the whole display. Or if there is a way which can stop the flashing of the broken part. I don’t mind if the color changes or not. It’s just the flashing part is annoying. Thank you for the help!!