RE: Too late to change peep sight ??????
Eightwgt- Take a marker or oil pen and mark where the peep is. You should have no problem at all with changing your peep. I worry more about you chaging your anchor. If your leening in now, and chenge he peep so you dont have to lean in you will change how you are anchored. This will effect your groupings the most. HOWEVER, with all that said, I would change it and just make sure you sight in real good again. You might be surprised that it wont change things at all...
I was shooting a compitition once and had my serving break. Rules were I had 15 mins to re-serve the string and 5 arrows to re-sight in.. Thats it! Believe it or not, I did it and never had to move my sight at all... Just make sure you have all your measurments. I think I finished with a perfect 300 and 49 x' s that round.