Hello Thanks for query . Based on the facts that you have posted dry ,rough scaly patch on scrotum is most likely to be due what is called as Jack Itch . Use topical anti fungal medication like Meconazole twice daily for local application . Wash your inner wares in boiling hot water mixed with anti septic solution like Dettol . Ensure to observe proper personal hygiene by cleaning and washing your genitals and private parts with warm water twice daily before applying Meconazole . Ensure to use loose inner wares and clothing Dr.patil.