The symptoms are suggestive of
Jock itch.
Jock itch shows up in post-adolescent men
and hormonal changes during puberty,lifestyle and heredity each play a role.Predisposing fungal disease like tines cruris may also aggravate it.
Keep your groin area dry and keep a separate towel for yourself. Most forms of jock itch respond to over-the-counter products, which contain any of several basic ingredients: miconazole, tolnaftate, terbinafine, and clotrimazole.