Thanks for your query.Based on the facts that you have posted it appears that you have Jack Itch as you have rightly thought of..
Please observe good personal hygiene with washing your groin and genitals with worm water twice daily
Wash your inner wares in Hot boiling water twice daily. mixed with antiseptic solution like Dettol
Apply some topical anti fungal ointment like Mecanozole twice daily. It should get cured in a week.
Get prescription of the medicaion from your family Physician.