...um

I'm stuck. I have the next scene I need to finish at least partly blocked out. I know what happens in general. I understand the scene after that better. I can't stop thinking about the scene I have already written - it isn't quite right. And I know what will make it better, but then - will I be up-ending entire pieces? This is a bit like a Sodoku puzzle that I've messed up. I know that there was a mistake at some point, but how many other mistakes has it caused me to make?