Hello and welcome to healthcaremagic
I would keep a possibility of Furuncle/boil, which is bacterial infection of the hair follicle with surrounding
cellulitis. The infection usually gaining entry through the hair follicle.
The best way to approach is to start on an empirical oral antibiotic for a week OR 10 days (My choice of oral antibiotic would have been
Amoxycillin 500mg in combination with
clavulanic acid 125 mg, thrice daily, for a week OR
Cephalexin 500ng thrice daily OR
Cefadroxil 500mg twice daily, for a week). This would take care of the infection.
An OTC antibacterial cream/ointment e.g 2% mupirocin can be applied twice daily.
An OTC pain killer e.g ibuprofen once or twice daily would help you deal with the pain.
If the lesion does'nt respond or continue to enlarge, it may have to be incised to drain the pus
regards