What is Tetanus Toxide used for?

Q: I recently got a bruise on my hand and was asked by my parents to take an ATS (Anti Tetanus Serum) injection. When I went to the medical shop I was told that ATS Injections do not exist now and have been replaced by tetanus toxide. Are both of these the same injections? Also I was asked to take the injection on my hand inspite of my asking for the injection to be taken on my back (as usually taken): any specific reasons for this? The injection led to severe pain on my hand for almost 2-3 days before the pain gradually died down to normal even though I have slight pain now i.e. almost 4-5 days after the injection. Why is this injection so painful?

A:Injection tetanus toxoid only is recommended as a preventive measure (to prevent the possibility of tetanus after a wound) after injury. There is no need to repeat it before a period of five years even if an injury occurs during this period. The injection does cause pain in some individuals for a couple of days, which is a minor irritant without any serious sequelae.