Even if you are already left-footed, you will discover quite quickly that driving with your left foot in place of your right is very, very difficult, even if you are used to driving with a manual transmission. I had surgery on my right foot and could not drive for 6 weeks. I considered trying to drive with my left foot and even practiced a bit before surgery (in an empty parking lot). I discovered that I could not drive with my left foot in a safe manner, even though I have driven a manual transmission vehicle for many years.
As this anonymous attorney said in answer to the same question:
“There are people with only a left leg who drive cars using their left foot to operate the controls. As long as you can safely operate the car using your left foot, there is no prohibition against your driving.
I do suggest that have someone drive you to a large parking lot after the businesses have closed and try driving using your left foot before going on the street. If you are accustomed to driving an automatic and not using your left foot, I can tell you that it is a very different feeling using your left foot, particularly on the accelerator, and the driving position may not be comfortable.”
Something else to consider is potential damage you might do to your already injured right foot by simply climbing into your vehicle, or by accidentally using your right foot because that is what you are used to using. Plus, if you are taking any pain-killers you need to be aware that your reaction time will be slower.
If your doctor says don’t drive, then don’t drive. Take a taxi or ask a friend to help.