You cannot overwrite the RAW, so the 'RAW' data is still there, assuming you didn't delete it.
What software are you using?
Lightroom, for example, saves the edits in a little sidecar file with an .XMP extension. The original RAW is still there, it just loads that sidecar (which is basically a history of what you've done) when you open the RAW.
You should still be able to go back to the unedited version any time. You could also just delete the .XMP file.
Other programs do the same thing, they just use a different file extension for the sidecar.
Adobe (I use Elements 9) saves them as DNG files which stands for Digital Negative file. You can save your RWA files to Adobe DNG files right within the Camera Raw window. It is one of the save options.