It can break. Thats why they're supposed to measure it when they put it in an remove it. Normally though, it has a better chance of breaking during removal. its well protected in your arm.
I had it before i got pregnant, i only had it a few months as my body didn't react well to it. But it under quiet a bit of skin and also the implant is flexible, it's between muscles so it's highly unlikely that it will snap or anything you should be fine!
I didn't even know there was a birth control that goes in the arm lol
I really dnt think its possible. Best to call the doctor and ask :)
This is a pregnancy forum so, most of us aren't on birth control. There is one for birth control you might get a better response there