hi. based from your description, it could be hiddradenitis suppurativa. this condition usually follows underarm shaving or irritation of underarms to strong chemicals of deodorants. it might resolve spontaneously, but some persists, and recur. avoid using deodorants with high aluminum content and avoid shaving/plucking for now until the wound completely heals. keep the area clean and dry as well after taking a bath. it is also best if you consult with a doctor, preferably a general surgeon, for clinical evaluation and management (proper antibiotic treatment and/or surgical if indications are found). hope this helps. good day!! ~dr.kaye