Hello, Thank you for posting on HCM. It seems you are having recurrent bacterial infection of hair roots called folliculitis. Hair in area of buttocks and lower back are prone for infection as they are constantly exposed to shearing friction and humid environment. I would suggest you a week long course of oral antibiotic like cefadroxil and clavulanic acid combination and application of mupirocin cream twice a day over affected areas. Use antibacterial triclosan based soap for rinsing those areas. Avoid tight undergarments and maintain hygiene. Hope this will take care of your issue. Wish you best of health. Thank you Dr Hardik Pitroda M.D Dermatology