When I was 16 years old I went to the oral surgeon to get my wisdom teeth pulled. I was nervous as all hell, it was going to be the first time I was knocked out. They checked my blood pressure and it was sky high, which is rare because I have extremely low blood pressure, to the point when I was younger I would faint. They were almost not going to do the operation, but went through with it anyway. So the stress from the accident could have caused you to have really high blood pressure.