Hi @rebeccaperth,
More than likely the screen has been damaged internally and it will need to be replaced.
Here's a [https://www.youtube.com/watch?v=YpsHOUO6kc4|video] that shows how to replace the screen.
Replacement screens are available online. Just search for ''Galaxy A20 LCD display'' to find suppliers that suit you best.
If you want to check if the display is the problem or if there's a problem on the systemboard then here's the ''no display troubleshooting flowchart'' from the [https://www.mobilerdx.com/2019/12/download-samsung-a20-a205fn-schematic-diagram-service-manual.html|service manual] that may help.
[image|2769529]
(click on image)