It would help us to know what version of MS Office you're running. 2011? 365? Home, Personal or University editions? I assume you're using a MS Office product on a Macintosh computer? (Not using Office on Windows in a bootcamp partitions?)
Have you tried opening the .tmp file in quicklook or textedit? What is the exact name of the .tmp file, are there other files?
After a little searching I found this webpage:
Automatically save and recover files
On the Word menu, click Preferences.
Under Authoring and Proofing Tools, click General
Make sure that the Confirm conversion at Open check box is selected,
and then click OK.
On the Standard toolbar, click Open Open button.
On the Enable pop-up menu, click Recover Text from Any File.
Open the document.
Failing that check and see what you have in your auto recovery folder.
In your Dock, click the Finder App once to focus it. Then on the menu bar (very top of the screen), click Go > Go to folder.
Copy and paste this in there:
~/Library/Application Support/ Microsoft/Office/Office 2011 AutoRecovery/
If that doesn't work, click Go while holding the option key on your keyboard, and Library should show up in the menu, (it is not there normally, it's a hidden directory) click on it. Browse to Application Support, then Microsoft, Office, and poke around in these directories for the auto recovery folder. Try using Quicklook to see if any files is magically working (click once on them in Finder and press the spacebar to Quicklook).
Give us more info and we might be able to help you better. At the very least you'll be better prepared in the future if you read that webpage I linked to completely.