Your derm is right- and too much application is not good either,you immunity being good do not worry about recurrences.
I agree with your dermatologist. Anal warts are small warts that can occur in the rectum.They are cauliflower-like protuberances and are usually symptomless.They are spread through direct skin-to-skin contact during oral, genital, or anal sex with an infected partner.
For small warts that affect only the skin around the anus, several medications(like podophyllum resin, Podofilox (Condylox), Trichloroacetic and bichloroacetic acids, Imiquimod 5% cream and interferons) are available, which can be applied directly to the surface of the warts.It seems that you had small warts only.So need not worry about them.
Hope it helps. Take care and pls do keep me posted on how you are doing or if you have any additional queries.Kind regards.