How do you fix a screen with dark, flickering horizontal lines across

So a few months ago I dropped my iPhone 5c and the top right corner had a very small crack and at first didnt seem to affect the screens light but eventually it started to have horizontal lines across the screen and the screen is very dark (I can still see what I was clicking on but it was difficult) and then after a few days the screen became unresponsive(all black) but it the phone would still make noises and vibrate, so my phone wasn't completely broken. About a week ago I started doing research and I read that if you take the cover off and press on the plate covering the cord that leads to the screen you might make it responsive again. This worked kind of because now the screen isn't totally unresponsive, it's just very dark and has horizontal lines running across it. Do I need a screen replacement? Do I need to actually unscrew the plate and look at the cords? Thank you!