original Blogger Tips

I would suggest going back to Blogger dashboard, click SETTINGS then PUBLISHING and change the blog URL back to the original blog URL. Of course you will need to do it fast because that option will not be available any more if another blogger has already registered that URL. If successful, all your original permalinks will be restored.

I have tested it at a test blog Computer Hardware Tips and Tricks and confirmed that after changing the blog URL back to the original, the permalink of the individual post had also been restored.