Welcome to HCM.
It looks to be folliculitis
occurs due to hair route infection.
It occurs usually due to scratching after severe perspiration,improper hygiene.
You have to take antibiotic like amoxy/clavulinic 625 to subside infection and nsaid
to subside pain,inflammation.
Take proper local care,clean it with antiseptic liquid and apply antiseptic cream.
Get examined by your doctor and start proper treatment.