Brain function

Hi, just wondered if you can advise if brain function can improve after a trauma. I had a motorcycle accident where I was dragged under a lorry and got trapped in a wheel. I don't remember anything about the accident but I obviously got a bump on my head through the crash helmet and then suffered with dizzy spells for around 6 months where I was told my marbles were settling back down again. I was given ketamine at the scene.
my memory is atrocious now and if I start doing something like turning on the tap and then think about doing something else like making a sandwich, I will completely forget I turned the tap on. it's really frustrating! Sometimes I don't even remember that I have forgotten something.
I have to write things down straight away at work that I get asked to do otherwise I haven't a hope of remembering.
it's nearly four years since the accident, will I ever improve or is this it now?
I am still having counselling which has helped a great deal to move on. got diagnosed with a form of PTSD.
Once you've damaged some brain cells, im guessing they've gone forever?
Thanks in advance for your response.
my memory is atrocious now and if I start doing something like turning on the tap and then think about doing something else like making a sandwich, I will completely forget I turned the tap on. it's really frustrating! Sometimes I don't even remember that I have forgotten something.
I have to write things down straight away at work that I get asked to do otherwise I haven't a hope of remembering.
it's nearly four years since the accident, will I ever improve or is this it now?
I am still having counselling which has helped a great deal to move on. got diagnosed with a form of PTSD.
Once you've damaged some brain cells, im guessing they've gone forever?
Thanks in advance for your response.