I am a doctor and I had a traumatic brain injury 5 years ago. I don't even like that term (brain injury). I have brain damage and my brain won't "get well". You don't want to live with brain damage and, thus, you don't want to box (see Muhammed Ali). You are much more susceptible to further and more extensive brain damage from boxing due to the fact that you have suffered a brain injury already. Indeed, I'd even advise you to be careful with the headers in soccer as they have been shown to cause diagnosed brain damage in long-term players. Further, as others have suggested, if you seek advice from your physician talk to several. Most M.D.s are ignorant of the causes, the severity, and the life-long consequences of brain damage.