Removing flash photography from my video

Hello everyone. So I recently filmed a wedding and towards the end of my edit, there are a lot of white flashes from the photographer. I figured out how to edit the flashes out and it looks fine in the timeline. However when I go to export the project, the flashes re appear in the final video. I've made sure that my frame rate when exporting matches my frame rate in the timeline and still have the same problem. What am I doing wrong? Thanks!