I think given enough recovery time you can get back to your previous state or better. It's important not to set unrealistic expectations that could lead to burn out. There's both a physical and emotional trauma aspect to this, I think you need therapy for both.
For physical trauma related to the brain, it's hard to say what is most effective. Typically, good nutrition and exercise seems to help--there's a body of research on this that I encourage you to look up.
Secondly, don't worry about how you used to be. I would rather just focus on the future and what you can do with your current state. If all else fails, there's solace (perhaps) in knowing that intelligence isn't necessarily required for success--to me it appears to be more a combination of luck and charm (kind of joking here).
Lastly, don't let your perceived loss become a self-limiting factor.
For physical trauma related to the brain, it's hard to say what is most effective. Typically, good nutrition and exercise seems to help--there's a body of research on this that I encourage you to look up.
Secondly, don't worry about how you used to be. I would rather just focus on the future and what you can do with your current state. If all else fails, there's solace (perhaps) in knowing that intelligence isn't necessarily required for success--to me it appears to be more a combination of luck and charm (kind of joking here).
Lastly, don't let your perceived loss become a self-limiting factor.