It seems that you are having folliculitis
It is an infection of hair follicles.
It may be due to friction of the area , fitting pents,poor immunity, poor hygiene,
scratching or some internal disease..
Thorough medical history and clinical examination may be needed.
Blood test may be done to rule out diseaes like DM,HIV,anaemia or other diseases.Oral antibiotics
50 mg twice a day for 2 to 4 weeks might improve the disease.
If you have itching take antihistaminics like levocetirizine
Avoid soap bath, use dettol for bsth.
Improve immunity with immunobusters and healthy diet.
Avoid worries and tension.
You will be alright.
Dr. Ilyas Patel MD