long term complications with tetanus shot

I had a tetanus shot in 1992 in the right arm. There was a small bump at the injection site that gradually disappeared in a year's time.

I got my next one in 2005 in the left arm. It hurt and burned much more than 1992's shot. Once again a bump formed at the injection site, but it did not go away.

I got a flu shot in 2010 in the left arm. The man who did it said he preferred the left arm because he was left-handed. I pointed out the bump, and he said that was no problem. He said it was just the same kind of scar that smallpox vaccine receivers got.

Now in the last month the bump has decupled in size and become sensitive to the touch. I can no longer lie down on my left side. Before I go to the doctor, I want to get a preview of what bad news I am in for.