edit marker failing to make changes to video, still using credits

It's using my credits still but when I try to make edits to a short video, it's not making the changes. For example I would tell it to make outside a little darker and it would go pitch black which ruins being able to see the trees and rain, then i would make the edit to make it brighter again and rain and trees moving visible outside the window and it wouldn't make any changes. I tried 5 different variations to re generate what I needed and it wouldn't do it but kept taking my credits.