Hi,
This could be due to folliculitis, an ingrown hair or a boil. Folliculitis is inflammation of the hair
follicle - it can occur during if hair get pulled out due to friction, tight clothing etc. Try not to squeeze
it. You should be extremely careful about personal hygiene. Application of antiseptic washes may help prevent
recurrences. A topical antibiotic cream, mupirocin (Bactroban®) applied twice daily for a week would help.
If this persists, you would need to get a clinical examination done. Regards.