Thanks for your question.
The issue is the screen itself. You'll not have to worry about replacing phone in full. Even after a drop an iPhone 5s' s motherboard (which is the brain of the phone and most importent component) should be fine.
There are two ways to clear up the virtical lines. You'll need to be a little phone repair savy for both.
The first: You will need to open the device and check the connector for the screen. It connects directly to the top part of the motherboard. There are four connecters there via flex cable.
Disconnect them, blow them out with compressed air and reconnect them.
-This will clear any dust or sediment from the connectors AND allow the connectors to be re-seated. Just incase the drop knocked one loose.
The second: replace the screen out-right.
-If you have a trusted cell phone repair provider, just replace the screen. It will save any headache in the future and the phone gets a shiny new display.
Hope this helps.
Would like to know if it does.