Mammo w/results today - first one since diagnosis- good/bad?

Mammogram today - first one since diagnosis on 12/2/2009. New lump on cancer side. They think swollen lymph node but radiologist is not sure, could be good/bad. Leaving it up to Dr. to biopsy. Mammo&U/S looked "good" to radiologist, but recommending MRI because breasts SO dense and cancer could be hiding.

Talk to oncologist next Thu, so now it's hurry up and WAIT. All in all, so far, so good.... Heart scan, find out results next week as well (to make sure Herceptin is not causing damage).

My question is has anyone had a follow-up with a swollen lymph node, had it biopsied and found it to be cancer? She would have said if it felt like "scar tissue" or found a benign finding so I don't honestly know why she is leaving it up to my oncologist. She definately is recommending the MRI in case there is cancer hiding in there.

Should I insist on a biopsy? Since I had ALH (atypical lobular hyperplasia) found close to the cauterized margin on my lumpectomy surgery, (and I know lobular cancer does not show up on mammograms), but do they show up on MRI's?

My HER2 is a strong +++ and my cancer was high grade (3), Stage 1 IDC with some DCIS and ALH. I am scared.

Sandra