Arrgh my camera broke

I'm taking a photography class right now, I have a Nikon FG... While I was rewinding the film, I pushed the wrong button and messed up, so I took it to the camera shop. They took it in the darkroom and got the film out, but then I was looking at lenses with the clerk and he took the lens off the camera... I've taken the lens off a lot of times before, but when I left, the exposure meter doesn't work anymore... I don't know if there are any camera people here.. but does anybody have an idea about what might be wrong?

Hmmm...I do photograpy, but im shit at cameras. I dont have one of my own yet (since they are quite pricy), I use the university ones, so all faults are fixed by my teacher or a technician.

I'll tryand find out for you what could be wrong.

Thanks Milla 😊