You said there was numbness in the edge of the knife. I don't know what the problem is. If the stitches are removed, see if the incision is swollen, and then press it slightly to see if it hurts. If there is no suture removal and dressing change, see if there is any special liquid oozing out. If there is no swelling, no pain and no fluid oozing, there should be no problem. If you really can't, go to the hospital for surgery.
I wish your mother a speedy recovery and hope it will help you.