if its a herp vet than they probably know best. If its a new lizard, it may take a while for it to be comfortable. Make sure it has hidey places, correct temps, and don't bother it too much. Mine will not come out of its hidey spot if anyone is around. Lizards can go awhile without food(not that its good for them) if your lizard is hydrated, it should be ok for a while. I don't know what food your offering, but try whatever food it normally ate befor it went off feed.
Hopefully, someone with more experience with plateds will post. I've only had my plated for a few weeks, but I have been keeping lizards for like 10 yrs.
Hope this helps.
T-spoon