I have seen lots of dry lips from Accutane, some mild involvement of the nose and eyes, but never dryness of the penis. On the other hand, the penile opening can get irritated by itself sometimes. I advise you to keep the area moisturized (e.g. vaseline), and show your doctor if the irritation isn't gone in 10 days. You might need something medicated (e.g. hydrocortisone.)
Best.
Dr. Rockoff
Thanks.