Go to a doctor before using a razor blade on your willy!
Warts often recur, whether they're on the penis or on the thumb. Just because they come back doesn't mean you caught them again. Why do they do this, and where are they between outbreaks, and are they catchy when invisible? All good questions, but there aren't any definitive answers. As to contagion, it's essentially impossible to tell in the individual case who gave what to whom or whether they even did. Besides, warts can incubate for months or years before they appear.
Bottom line: show your next bump to a doctor knowledgeable about warts. Be as sure as you can that that's what the bumps actually are. Don't think of this as "coming clean"--to a doctor, this is just a common diagnosis, nothing to be ashamed of.
Best.
Dr. Rockoff
Are you 100% certain it is a wart? Have you had a biopsy and test for HPV?
I have not mentioned it to my doctor since that one visit back in '92.