Can The Bruised Scar On The Elbow Be Malignant?

Hi, I am writing this for my mother, she is 43 years old. When she was a child she was treated by a doctor who gave her a vaccine, but ever since that Doctor treated her, the scar remained there on her elbow up until now. and a week ago, she went to the laundry and when she closed the washer door, she hit her scar and it left her with a huge bruise. She told me that when she touches very softly it hurts her, the skin tissue is really delicate. And as of today, when she was getting off of the bus, she bumped into one of the metal doors by accident, and now her brusie is expanding... What we are most worried is if this scar is malignant. My mother told me that when she touches a specific place of her scar, she feels like there is a hole, like there is no muscle underneath or skin tissue. We are really worried if this is going to get worse.