After I had my TT, I was feeling a little hyper and I asked my surgeon about it. She said that she had to squeeze my thyroid a little during the surgery, and this releases a little surge of hormone. She said the symptoms would pass in a couple of days, and they did. That may help explain your elevated BP, but it’s been more than a couple of days since your surgery now.
Have you already started on thyroid hormone replacement? It takes a couple of weeks for your body to use up the hormone that’s already in your system, so if you are taking replacement hormone as well (as is often the case) you’ve got thyroid hormone from two sources. I didn’t start on my levothyroxine until a week after my TT, which I think was actually due to a miscommunication. When I called and asked about getting my prescription, they called it in to the pharmacy right away.