I got a tetanus shot a few months ago. I have fibromyalgia and mixed connective tissue disease. I have been putting off getting a tetanus shot for a long time but got bit by a stray cat and had no choice but to get one. I did not have any weird reactions but I can tell you that my arm was so sensitive for over 2 weeks. My arm hurt a lot and had a hard time sleeping so I took some darvocet that I had left over from a hip injury. I am sensitive to shots even the flu shot I get pain from. I have a flu shot tomorrow and I know my arm will get red puffy and painful for a week. Overall...... I would recommend the tetanus shot. Not sure what meds you are on but if you can maybe some Ibuprofen for pain or something stronger to help with sleep. I couldn't lay on my arm for 2 weeks.