I think you'll have to use catheters and a leg bag for a few days until it heals.
The external caths look like a condom with an opening on the end to hook up to
a hose, which then hooks to the leg bag. They stick to your penis with adhesive.
Or you could use an internal foley cath, again, hooked up to a leg bag.
If you're incontinent, you're doctor can help you decide which kind will work
best for you. I'm surprised the doc did not already recommend caths for your
incontinence, most doctors steer guys away from diapers, due to possible
problems with skin irritation. (ummm, diaper rash.)