Welcome to HCM,
From history it seems that you might have infected Sebaceous cyst
giving rise to this problem.
Continue proper dressing with antibiotic and antiseptic lotion prescribed by your doctor.
To clear infection go for antibiotic medicine course for3-5 days.
If it is a boil or forming abscess
,it will be alright.
If lump does not clear or recurrence is there, consult surgeon and get it removed with sac.
Ok and bye.