Thanks for writing your query.
After reading your post, it seems that you are having Dermatitis
in the area described by you.
It needs proper medical management.
You should apply locally cream containing antifungal like miconazole, steroid like betamethasone
, antibiotic like gentamycin
. This cream should be applied locally 3-4 times a day for atleast a week.
Also take care of your personal hygeine. Have bath daily with medicated soap.
Change your clothings daily.
If the problem persists, get yourself examined clinically by a dermatologist
I hope this is helpful to you.