I can't really tell you for sure without seeing these, of course, but a nurse at an STD clinic would certainly know what warts look like. Also, warts are usually raised, at least a little bit. If you need more reassurance, I advise you to see a dermatologist. It's more than likely, by the way, that the "wrinkled" appearance of your penis is just what that part of the body looks like only you've been concerned about the area and are looking harder than usual.
Take care.
Dr. Rockoff