How to fix screen failure after fall from my bed

My macbook dropped out of my bed like 2 days ago.

After the fall everything seemed okey. So i continued using the macbook.

The day after i had a school day and had my macbook with me after using it for a while i had a short break so i closed the screen of the laptop. so when i came back i opened the macbook and the screen was making lines al over the screen. so what i did i went to my local apple premium reseller and had a look but the lines were gone.

when i came home and used the laptop again the lines came back.

so now my question is what is going on.

Should i replace the screen or is it maybe the logic board.

I really hope you guys could help me out.

Edit: When the screen is doing weird and i connect it to a external display everthing seems fine.