My Five Year Old Daughter Fell Approximately A Month And

My five year old daughter fell approximately a month and a half ago while at school during recess. She obtained a bruise on her cheek. However, I recently noted that there is still some purplish red discoloration there and there is a quarter sized knot under her skin. This injury did not break the skin, but you can tell when you look that there is discoloration where the injury was incurred. Should I be concerned about this? It does not appear to hurt her, but I am worried she is going to be disfigured from this knot under her skin. In certain lights, you can see it doesn't look quite right.......