Mondor's Disease (venothrombophlebitis) sounds scary but isn't life threatening
Occasionally, a "cord like" structure will develop perpendicular to the base of the breast and extend inferiorly, over the rib cage onto the abdomen. It's more frequent when the breast incision was made at the inframammary fold and if the individual is thin. Treatment is symptomatic: warm heating pads, NSAIDs (Motrin) when cleared by
your PS and "tincture of time". Wait it out and it will resolve. Do confer with your PS for his/her advice. Good luck.
Mondor's cord after breast surgery
Without pictures or an in-person exam, there is no way to answer your question but it sounds like what you are describing is called a Mondor's cord. These usually go away without intervention but rarely a cortisone injection is needed. Follow your surgeon's advice since he or she is the only one who can actually treat it. Swelling is often asymmetrical for a period of time after revision surgery.