My almost 4 year old bumped against a dull/rounded table corner about a month ago, causing a bruise on the bone under/ her eye. It was a pretty small one, maybe the size of an adult fingertip, and didn't cause any other injury or issue. It has mostly faded, but there is a still a small light brown spot left, about the size of an eraser, that doesn't seem to be going away. It doesn't bother her at all, it's not sore or hurting, but it's there. I haven't seen a bruise take this long to go away before. Is there any reason for worry here? Pic attached for reference (right side of her face, looking at the picture/left side in RL)