Undo repair balance history?

Is there a way to undo repair balance history? It looked like I had many account mismatches but when I repaired them it merged my manual treasury direct account into my retirement account. Is there any way to undo this?

In Google Sheets, you can always go back in time to before you made the change. Just go to “File/Version History/See Version History” and pick a time from before the change to restore. Of course any other changes you made since that time will be lost as well after restoring the older version.