Hi,
Thanks for writing to us.
Groins and genital area as such are darker then rest of the body and due to chronic itching and inflammation it has darkened further( post inflammatory
hyperpigmentation)
you may treat the area by using depigmenting cream like
Kojic acid in morning and
hydroquinone 2 percent in night. Use the same atleast for few weeks to notice response.
Hope that helped.