Thanks for writing to us.
The lesion is a Folliculitis
in your pubic area. Folliculitis is inflammation of one or more hair follicles. This occurs due to infection of the hair follicles by bacteria. It might be precipitated by rubbing from clothing, blockage of the follicle, or shaving.
It is very important not to touch or burst the eruption you have. Everytime you do it, you are actually inoculating more bacteria from and into the surrounding area. Pubic region is an area more prone to contamination and infection.
For the treatment, you will need to visit a dermatologist
who will prescribe appropriate oral antibiotics
to eradicate the infection. A culture from a swab, taken from the swelling might also be required.
At home, can clean the area with normal saline and do a few warm moist compresses to reduce inflammatory swelling/pain. You can apply a topical antibiotic
cream like Fusidic acid
or Mupirocin 2-3 time daily.
I do hope that you have found something helpful and I will be glad to answer any further query.