Child Hit Bone Under Eye, Swollen, Bruised. What Might Be The Cause?

My daughter s foster child fell off a trike and hit the bone under her eye on Thursday noon. It left a small, less than pea sized red mark. A cold pack was placed on it. The child was playing, talking, interacting and laughing less than a minute later. The mark was still present, but unchanged when the grandmother took the child for the weekend on Saturday afternoon. Sunday evening when the child was brought home, her whole eye was swollen and bruised. The tiny mark from the first incident is still visible but unchanged, slightly below the new bruise. Is this a new bruise or could it have been caused by the first incident. The child is 2. She is seeing a doctor later today.