A large area of redness and pain in the armpit is considered to be related to herpes zoster, boils, etc. The treatment should be based on the cause of its onset through general treatment, medication and other ways of treatment. 1. General treatment: patients should pay attention to not scratching the local area with their hands, so as not to cause skin breakage and other bacterial infections, pay attention to rest, do not strenuous activities. 2. Medication: (1) herpes zoster: if the local manifestation of strip-shaped distribution of blisters, accompanied by obvious pain, we should be vigilant about the occurrence of herpes zoster, this time, you can follow the doctor’s advice to use acyclovir, vaxilovir and other antiviral agents, the pain is obvious, you can use ibuprofen and other pain medication symptomatic treatment. (2) boils: if the local manifestation of redness, swelling and pain obvious hard nodules or abscesses, we should be vigilant about the occurrence of boils, in this case, we can follow the doctor’s advice to use ichthyolite ointment, erythromycin ointment and other antibiotic preparations for external application, combined with cephalosporin and other preparations. Surgical incision and drainage is required for abscess formation. For the armpit of a large area of skin redness is very painful patients, it is recommended to the regular hospital dermatology, clear cause of the disease under the guidance of the doctor active treatment.