Sounds like you need a new vet.
Did he nerve block only the foot, or did he work his way up the leg? Often when the offending part of the foot/leg gets nerve blocked on one side, but the horse gets worse on the opposite legs, it's in both legs; not just one. Is that what happened?
Did he do an x-ray?
And the vet is telling you a big fat LIE if he tells you your horse is not in pain. Why does a horse limp? Because something is painful and they are trying to compensate for it.
Also, who put on the wedge shoe on your horse? If it was your "regular" farrier not used to complicated lameness cases, it may have not been done right.
∞•*˚ Βгįťţαňγ ˚*•∞
It is not enough to know how to ride; one must know how to fall.