The hard edge of the scar after breast surgery may be a normal phenomenon, or it may be related to scar hyperplasia, thread knots and so on. 1. Normal phenomenon: Due to the relatively poor local lymphatic and venous return of the breast, after the surgery, it will lead to an increase in tissue fluid in the incision area, and the absorption of the tissue fluid will take some time. Before it is completely absorbed, it will accumulate at the edge of the scar, resulting in hardness in the area. 2. Scar hyperplasia: If it has been 3 to 6 months since the surgery and there is still hard scar tissue, you need to consider that it is caused by scar hyperplasia. It is common in patients with scarring, manifested as a purplish red bulge on the edge of the scar, similar to earthworms. 3. Knot: Surgery usually requires the use of double-layer suture, if the suture line is not completely absorbed, or there is a knot, it will be manifested as a localized hard phenomenon. It is recommended that patients observe more, if there are obvious symptoms of discomfort, you need to consult a doctor in a timely manner, under the guidance of the doctor to standardize the treatment.