I am having lumpectomy surgery and need advice abot healing?

Minimal. Agree with doctor rosen. After surgery, complications such as infection, bleeding into the lumpectomy cavity can occur. So wear a support bra can help minimize this a bit.
Minor Surgery. While this may be anxiety-provoking, the actual operation is quite small(~30 min) with minimal postop pain (non-narcotic pain meds usually sufficient, especially after 1-2 days), and a quick return to work(1-3 days) and normal activities(7-10 days). Of course, your "expert" is your surgeon--he/she will know the specifics of your operation and your overall health, and will guide you appropriately.