Thanks for using Healthcaremagic,
These are due to infection by staphylococcus
commonly due to perspiration and moisture may start from hair follicle.
This infection can cause collection of pus or may involve local Lymph nodes.
Treatment involves judicious use of antibiotics, if the one you are using is not tolerated then alternative can be used.
To reduce pain and swelling analgesic
and anti inflammatory drugs are commonly used.Abscess
formation may require surgical drainage
to remove pus and repeated dressings are required for healing and keep personal hygiene and keep area dry as far as possible.
If problem is recurrent one then possibility of Hidradenitis suppurativa
condition pus collection occurs repeatedly.
Hope this is useful to you.
Dr.Akhilesh Dubey M.D