These small white bumps can be folliculitis, acne or as your doctor has said, perioral dermatitis. Treatment for
all three however is topical and oral antibiotics. Even treatment of perioral dermatitis
is by antibiotics like doxycycline.
Folliculitis is caused by blockage of the follicle. In most cases of folliculitis, the damaged follicles are then infected with the bacteria Staphylococcus (staph).
First of all keep the area clean. Also use mild soaps like Dove.