The fact that there was no brain injury
on CT is a good sign. However am worried about him sleeping so much. If he is not on sedating medications I would expect him to be more alert. Decreased level of consciousness or drowsiness
is an indicator of brain injury.
The external swelling may be more alarming to look at, but does not really matter in long run. once the inflammation subsides it will go off. The routine anti-inflammatory medications should be able to take care of that.
If drowsiness persists, then scan may have to be repeated. If foreign bodies are not metallic, I would prefer a MRI