As for lymphedema just going away on its own: probably not. It’s the sign that your system just isn’t handling the trauma its undergone, and needs some help. Luckily, as the incidence of lymphedema becomes lower and lower, due to less and less invasive surgery, the treatment also becomes better and better. There are very few cases of the “elephant arm” that years ago used to be a terrifying side effect of breast cancer surgery. If you think you have lymphedema, see your doctor, and ask for treatment. Many health care facilities now have physical therapists trained specifically to treat lymphedema; one of these therapists can almost certainly help you get it under control, and hopefully even banish it completely.
Fast FAQS: Introduction to Lymphedema