A pimple growing in the armpit especially painful may be caused by folliculitis, boils, herpes zoster and other diseases, can be treated by oral medication, applying medication. 1. Folliculitis: Folliculitis is caused by bacterial or fungal infections, resulting in red pimples on the hair follicles of the patient. For fungal infections, apply ketoconazole ointment or tretinoin cream; for bacterial infections, mupirocin ointment can be applied, and you can take oral antibiotics or antifungal medications. 2. Boils: Boils are usually caused by aureus infection, which survives on the surface of the patient’s skin, and the bacteria will enter the mouth of the hair follicle after scratching or abrasion of the skin, thus triggering boils. Early treatment without pus can be carried out with ichthammol ointment, mupirocin ointment, and with oral antibiotics. It can also be combined with physical therapy, such as far infrared rays. 3. Herpes zoster: Herpes zoster is usually caused by varicella zoster virus, resulting in a red rash on the patient’s skin, accompanied by intense pain, can be treated with local application of Penciclovir cream, oral aciclovir and other antiviral drugs. At the same time, you can also take oral ibuprofen capsules, diclofenac sodium extended-release tablets and other pain-relieving drugs treatment. Patients with acne need to seek medical treatment in time to clarify the cause of the disease, and then follow the doctor’s instructions on the cause of the treatment, not unauthorized use of drugs. All of the above drugs should be used under the guidance of a doctor.