Hello, This is Dr Manish Nigam, Surgeon from Noida...actually if this swelling of yours was there for a few months but painless initially...n later on became painful...then it's most likely an infected sebaceous cyst...which has to be removed surgically....or if it appeared suddenly in a time span of 3-4 days only...then it's more likely Folliculitis which occurs due to plucking of hair n then follicle get infected...so to confirm the diagnosis you should get an Ultrasound done of this area...n then consult.
Next Steps
USG and USG guided FNAC & Culture sensitivity of the aspirated material.
Health Tips
don't take over the counter drugs/ self medications