John:
An itchy spot on the scrotum is usually eczema. Perhpas the cream you're using is OTC and too weak. Maybe you're defeating it by scratching. Why not see a doctor, get a definitve diagnosis and treatment?
Meanwhile, apply 1% hydrocortisone several times a day, moisturize at least twice with vaseline, and never scratch. If that doesn't work in 10 days, see a physician.
Best.
Dr. R