I'm not sure if you can.
What happens if you open the paper from the email again? Is it the amended version you saved, or is it the original?
This might be a hard lesson learned. Never open attachments direct from emails. Always "Save as" first, (to virus check them if they are from untrusted sources, even your own), then work on them from the temporarily saved location.
Perhaps others here will have better ideas for recovery.
Here's what happened:
I was working on a paper at school.
I saved the paper and emailed it to myself so I could work on it at home.
I opened the file from the email at home and worked on the paper.
Here's where it gets unclear. I think what I did next is instead of saving by clicking "save as" I just clicked save and the file saved under the temporary file name that Word gave it when I opened the paper. This all happened last night. Now I can't get the document back. Am I totally screwed, or is there anything at all I can do? I'd appreciate any responses as soon as possible. Thanks so much in advance.