Best diaper rash cream?

Hello beautiful mommies!
My son 2.8years old has rash & his testicles are red, feel hard to me & have shrunken what do i use? He feels itching on this area. I always keep him very neat and clean and diaper free all the day. This is not clearing up. It’s not getting worse, but not improving. Especially on the under side of his scrotum. Very bright angry red.
Please guide!! Thank you :kissing_heart: