Although it is said that the first week should be done nothing and protect the eyes carefully after the prk surgery and the eyes will get the full recovery after a month. I still suggest you not to drive until two months after you get the prk surgery because driving will take a lot of efforts for you to use the eyes which may cause the tired eyes that may affect the vision. Thus, you'd better wait for its full recovery.
Well, it seems that your eyes have gone through terrible disorder and are still recovering right? Therefore, what you need to concern is not when you are good to go, but what you can do to make them recover better and faster. However, generally speaking, it will take about a couple of months before you are ok to drive a car after receiving prk surgery. And before you do that, go and consult with a doctor.