I was watching a TED talk on you tube a couple days ago about memory, and the places where skills and long term memory are stored in the brain are very different, which likely explains why you haven't lost both the skills and memories... but as to remembering things that were in your high school years, I'm not sure. It is possible that brain damage could have taken them from you forever, because if certain connections between neurons are severed, they would have to be replicated exactly to reproduce the effects they had before (regrowth of neurons and connections is possible, but to make them the same as they were before seems unlikely). If the connections are severed in your brain, lucid dreaming will not be able to help you, however if they are only damaged, then the memory may come back on its own, or with effort. If your doctor said not to strain too hard, I would probably avoid working at it for at least a few months after the injury, as you don't want to cause more damage trying to recover memories that are being repaired by your brain.

I am not a neurologist, but I do have an interest in the field... I hope this helps, and hopefully you remember the good times.