I Got In A Serious Racing Accident A Couple Of

I got in a serious racing accident a couple of years ago, getting three areas of brain damage. I think some of the after effects are starting to show up. I have been getting the sensation of a lot of pressure being applied upon of my brain for a while now. I mentioned it to my doctor but he just said it was dehydration, and I immediately began drinking more liquids but it didn't fix anything. Do you have any idea of what may be happening or the cause of it?