My Cat Had A Bad Bite At The Base Of His Tail 1 Year Ago And Now Has Either Developed A Hate For His Tail, Or Has Sharp Spells Of Pain Causing Him To Lash Out At It. Help?

He is a 3 year old male tomcat and have been giving him downers like phenobarbital and others, but x-rays show no break and can't seem to find out why he suddenly yelps with pain and attacks his tail. I am trying to research the nervous system to see what nerve damage could have brought this on, but can't seem to find anything. Do you think amputation is an option, and what are the chances it will work if there is nerve damage? Someone please help my poor baby...