3. The marker is so that future mammograms/MRIs will show the exact area looked at. If you
get passed from doc to doc and have several tests, it keeps everybody on the same page.
When I had a biopsy, I did not bruise much at all, but it hurt like hell. And yes, I did have breast cancer. As far as your bruising, you may just be easy to bruise, or perhaps the biopsy needle passed through a vein that bled under the skin more than usual.
Yes, cancer is very much a possibility, but try not to panic yet. I say that, but I know you are probably freaking out. You'll know tomorrow. Please let us know how it goes (only if that is OK with you, obviously).