My project can't access my scripts after I change version 2 times

Firstly this project is my first project so I am beginner. Today ı had a problem about SDK error. Then ı tried to fix it, I wasted my time in 5 hours ı got nothing. And then ı decided to download unity 2020 beta version. İf you ask why did you download beta version? Because when I applied the SDK path on external tools unity says update your android or something(ı can’t remember now) tools. And then ı found 2020 beta version. And then ı change my project version to 2020 beta. Then I try to run project but it couldn’t. Because unity couldn’t access to scripts unity says( image). Then ı changed 2020 version to my old version. The same thing happened again. Pls help me I made a lot of effort to this project. I need your your help please!

You can’t use scripts in the inspector until Unity can successfully compile all the scripts. The error says you have compile errors you need to fix first. Check the console for the specific compile errors. Those have to all be resolved before you will see your scripts update correctly in the inspector.