Ouch Update.

Thanks for suggestions E, C.
Back from doc. More antibiotics (higher dose of same), referral to breast clinic tomorrow morning for assessment.
It's probably a blocked duct, but it could be an abscess, so need to get checked out.
Meantime, hot compresses are helping, as are copious quantities of ibuprofen. No cabbages in the locality, but picked up some spy leichtin capsules. Also acidophilus, cos the antibiotic is predictably affecting one part of my anatomy....