not much chance ...
I don't really have much hope to offer.
If you were using the document as a template and saved it instead of using Save As, then there would have been some recourse:
1. If you realized what you had done before closing the file, you could Undo back to the beginning, resave, then Save As and Redo back to where you were.
2. If you had already saved and closed the document and had "Automatically create backup" enabled, then you could look for the "Backup of <filename>.wbk" file, which would be the previously saved version.
But if you created a new file and unintentionally saved it with the name of an existing file, then there's not much you can do.
The .asd (AutoRecovery backup) file is used only by Word when it crashes ... it is presented to you automatically the next time you start Word. But you cannot open it yourself and find usable data. Word does create some temporary files while you're working that are copies of the document, but these are deleted when the file is closed.
Sorry ...