My Daughter Is 5 Yrs Old. She Has On And

My daughter is 5 yrs old. She has on and off gotten bruises on her lower spine that have come and go. She currently has what looks like a bruise but she has had it for at least the last 2 months and it is not going away. It is soft and squishy and feels like tissue (in my opinion) under her skin. Is this something I should be worried about?