Thank for asking to HCM
I really appreciate your concern, if the lesion is filled with pus then this should be treated with the oral antibiotic if I would be your doctor then I would treat this case with the following medicine,
1) Tab Ciprofloxacin
500 mg twice in day for five days
2) Tab Ibuprofen
400 mg three times in day
oint. for local application
do not try to apply anything which could hurts the area because this is very tender part can be easily traumatized, hope this information helps you, take care and have nice day.