This sort of incident, while potentially serious, usually is not, which is why the doctor has taken a fairly casual approach. If there are no symptoms and if the spot hasn't changed in terms of swelling, coloration, etc., then there's probably no cause for concern. However, one should always be watchful for 36 hours after a bump like this, looking mainly for behavior changes, excessive sleeping, and unsual vomiting. Anything grossly out of the ordinary should send up a flag. Absent symptoms, just be supportive. Good luck to you.
John Kenyon, EMT, CCT
Non-invasive cardiology tech, Emergency and Critical Care technician, Critical Incident Stress Mgmt. specialist