My Son Fell With Icy Condition On The Concrete Step..He

My son fell with icy condition on the concrete step..He hit his forehead. He had egg size bump. We wnt to Pediatrician and she said since he does not have Omiting, dizziness he should be fine..In any case she asked us to get X-ray done..which we did yesterday night...The X-ray probably showed no fracture., but they said they will send report to Pediatrician. but today most of the bump is gone. but if I put ginger I feel dent, not visible from outside yet..Any concern of injury?