I don't recall if anyone suggested or not.. But the gums of iguanas with recessed jaws like yours are prone to mouth rot.. I gently using a nice wet sponge on that upper jaw several times a day will help a lot.
I should also point out.. If you are not sure on expenses, your personal time involved etc etc in trying to keep this ig alive, you might want to consider letting it go.. I have seen people keep MBD igs going for many years but its always a gamble.