My Iguanas Tail Is wilting?

My 5 year old iguana is getting pretty big now, hes about 3 and 1/2 feet, he suffered a tail injury from the fan blade whale he was trying to attack me :) He got a pretty good slice on the top and bottom of his tail about 6 inches from his tip. a li bit of meat came out, but i bandaged and treated him accordingly. there has been no infection, but the tip of his tail has wilted. it has become a little grayish, and hard, and will not bend. the bones in his tail are showing, and it looks like a lil gray twig. but hes happy, and seems to be unaffected. IVE CALLED OVER 20 REPTILE SPECIALISTS, AND IM GETTING MIXED ANSWERS. they say hes developed gangrenous infection (isn't spreading, just getting skinnier) and that i need immediate amputation. whale others say that the meat that came out was the blood supply to the end of the tail, and its just going to fall off (below the original injury) The VET recommended by a specialty breeder wants 500$ to amputate, but i am not shure its necessary. money isn't really a concern, but I don't wanna shell out 2 weeks pay for something unnecessary. what should I do? Any experts out there? P.S (although my iguana is mature and large, he is still my first iguana, i mainly specialize in Monitors. and ive never had this kinda crap happen to an injury.)