I know brain injury can cause an impact on mental health issues - it's always been on my intake paperworks at T or P as far as I can remember. I did not have a hematoma but suffered a traumatic head injury (blunt impact, not a situation related to abuse) and I report that. I don't think it has caused any issues - aside from the memories I had in the hospital which is never fun for a 4 year old. I know in somatic therapy pre-verbal body trauma can be processed, so that may help - even drawing and that sort of stuff can assist in processing the emotional parts of that. Even minor falls can cause hematoma, that's why getting a head injury checked out is extremely important - it is absolutely not always due to abuse in childhood and I sincerely hope that abuse was not the cause of your injury. I'm glad it was caught in time.
Here on this page there is a chart of different Physical, Cognitive and Emotional impairments due to childhood TBIs.
http://www.biausa.org/brain-injury-children.htm