I have some information from Hughes, Mansel and Webster's book: Benign
Disorders and Diseases of the Breast: Concepts and Clinical Management.
Bailliere Tindall, London, 1989. They say that subareolar abscess is an
uncommon cause of breast lump in an adolescents. Treatment is as
conservative as possible with drainage / aspiration of the initially sterile
abscess (which may become secondarily infected). If  a fistula (permanent
opening) becomes established, excision of the fibrous track and the affected
milk sinus is usually curative.

Lisa Amir
GP / LC from Melbourne, Australia