Acne or  pimples... Due to hormonal changes..Oily skin causes it...Common in adolescent age...May occur in adults also.. Food like Oily foods, ice cream, chocolate and sweets increase it.. Treatment depends on the grade of pimples or acne..So, please  consult me in my clinic or consult me by direct online consultation by sending photos as it's a must to see which grade of pimples or acne for accurate diagnosis and treatment

It COULD BE an infection of the hair follicle in the peri-anal 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 OR if it continues to worsen over the next few days 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.