I am not sure what you are asking as the terms you are using are unclear to me but:
If you have changed the scale your clip, in the viewer click on the Motion Tab at the top of the viewer and set the Scale to 100%.
If you have changed the display size of the viewer, click on the button on the top left of the viewer with the % number and choose "Fit to WIndow"
Thanks, and, the scale is reading 100; that hasn't changed.
I haven't changed the size of the viewer window; I just went to "View" at the top of my screen and selected "Zoom in" from that menu. That blew up the clip in my viewer window several fields, but I can't find a way to cancel the blow-up, or restore the image in the viewer to its pre-blow-up (camera-original) size.
"Zoom out" will shrink the image and surround it in a matte within the viewer window, but won't restore it to it's camera-original size.