if you keep your fish in the least stressful conditions as possible it should survive. but, depending on what this "metal thing" is, it may not.
do these things and it should help:
*don't watch your fish too much, poke at the tank or tap at it, don't put any new ornaments in and pretty much leave the tank as it is.
* if you don't already have a hiding spot for your fish you should put one in, a cave or even a small terracotta pot on its side works well. i hav a plastic diver helmet in my betta tank and my fish loves it!
*plants, my betta's loves hiding in its plant, if u don't hav any i suggest getting one.
*don't feed it too much, if they are in shock they usually wont eat. just give your betta one or two pellets or flakes a day and if it begins eating then you can increase the amount. remember: you don't want to make your tank dirty by giving it heaps of food just in case it will eat. if your fish wants to eat it will eat wat you put in. try live foods like blood worms or something cos bettas like them.
*keep the tank clean, think like this, if you were extremely afraid or shocked, you wouldnt want to live i a dirty house, would you? but dont replace too much water at once because an already shocked fish wont bare very well with a sudden change in water temperature. so if you change like a cup or two or three (depending on the size of tank) and replace that with the same amount of clean water it will be better.
*finally, just watch him. if he gets worse then do all you can but if it doesnt make i you have to realise that fish die and it wasnt your fault. so cheer up and buy another. and dont pu t that metal thing back in!
>hope i helped<
