Could the hospital have switched my CT Scan with someone else's

I had a CT Scan on my orbits. the results contracdicts with my condition. The CT Scan shows that everything is normal, but I have unilateral proptosis. what are the chance that the hospital switched my results with someone else's?

NONE.

Swelling in the eyes does not have to be caused by the bones, and that's all a CT scan shows. The bones.
It does not show the tissues, you'd need an MRI for that.
All an orbital CT scan will show is a bone tumor or bone fracture, or normal bone structure.

In modern hospitals, the chances of getting a CT scan mixed up with someone else is fairly low- most hospitals have fairly good policies in place to stop things like this happening, and are pretty careful with how their records are handled. That said, occasional mistakes are made and it's not impossible.

The other possibility of course is that the scan simply didn't detect the problem. No scanning routine is perfect, and some conditions slip by some scans. Depending on the condition and scanning protocol used, there is no guarantee that everything will be picked up. Diagnostic imaging is simply another tool, it's not the be-all-and-end-all of diagnosis.

With digital CT records that is virtually impossible as you type the patient name into the computer before you even start the procedure. The days of results on an actual film are long gone, everything is on a computer. Talk to your MD.

Pay for an MRI.