"Days" Most women who undergo a lumpectomy may return to work in 2-3 days and be back to normal activities in a week (provided that was the only operation performed). The true "expert" to answer this question would be your surgeon since they may be aware of some nuances about you or your operation that may affect your recovery. Good luck!
Lumpectomy. Just to add to the other answers, if you have any questions about your own recovery, please contact your surgeon or primary care physician. Sometimes there can occur a bit of bleeding, bruising underneath your skin and it can spread out (usually because of gravity) this may or may not be tender. Usually this area of blood goes away with time just as a bruise does. If you are concerned see your dr.