Hematoma is a complication of surgery. This can occur when hemostasis is not completely controlled. This can produce pain on the surgical site as a result of pooling of blood and stretching of the surrounding tissue. Pressure dressing can be applied to help resolve this. If the hematoma is big, there may be a need to evacuate the blood clots. Pain reliever may also help relieve her of any pain. I’m pretty sure your mother will be ok.
Please do post the result of the biopsy.
Good luck and stay positive.