I have often wondered about this myself, but I have no answers.

My blood pressure has also increased quite a bit since the concussion, but it's starting to get back to normal (6 months later). I monitor it daily with a cuff.

Recently, I have discovered that sugar makes it skyrocket. I don't know why this is, but I abstained from sugar for a day, and my BP was normal for the first time in months. I repeated this trial a few times, and each time, my BP was normal on the days I didn't have sugar.

I had a point to my story, but I can't remember what it is now lol. Sorry. I'll edit this post later if I remember.