What Causes Patches And Itching Around The Groin?

I've developed a series of marks around my groin , they fell like the skin has sunken in certain places and it can itch intensely , especially during night time , i was prescribed by the doctor to take penicillin and use lice cream around the area as she and 3 of her colleagues were unable to determine what it was
I've finished all the medication and its still there
I have photos if you want to see

thank you for helping