One month after explant of 15 yr. old saline hard raised enlarged lymph under arm

It could be, but it could also just be swelling within the lymph node as a result of the surgery (ie, without silicone particles).  Time will tell.  If it goes down over the next few weeks or months it was the former; if not, you have to consider that it is a granuloma and therefore have it removed for biopsy.If there are no acute symptoms (fever, chills, sweats, redness, drainage, etc) then you have time to let it declare itself.  Otherwise, you may need to undergo intervention sooner.  You should of course remain under the guidance of your own plastic surgeon.I hope that this helps and good luck,Dr. Alan EnglerMember of #RealSelf500