Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice. It seems that your son might have some worm infestation giving rise to itching and soreness around the anus.
Give him some anti helminth medicine. Apply antibiotic cream on the part. Avoid constipation
Hope I have answered your query. Let me know if I can assist you further.
Dr. Ramesh M.Vachharajani