There is an infection of the hair follicle in the axilla area. You will need a course of oral antibiotics like Augmentin 625 mg twice a day for 7 days and apply Fudic cream 3-4 times a day. If after seven days the condition does not resolve and if it continues to worsen you might have to see a surgeon for draining the pus collection in the area. Also need to know if there is coexisting diabetes in the patient and need to know history of any drug allergies. I would suggest to get these details cleared up with a doctor before starting the treatment. Hope this is helpful.