Martha,
The breasts I've seen that have been drained for abscess have healed
nicely.  The wound remains open a little longer with the leaking milk,
but the milk seems to keep the wound clean, uninfected, and it does heal
just fine.

Depending on the site of the incision, mom may need extra help with
positioning to keep the baby off of the wound.  If mom cannot nurse
comfortably, she may need to express for a few days.  The milk she
expresses is safe to give to the baby.  Sometimes a breastpump is
irritating to the incision and hand expression works better.

Good luck.
--
Jeanne Mitchell, LLLL, RN, IBCLC
Austin, TX
"Be kind, for everyone you meet is fighting a harder battle."
Plato