If you literally have nothing else at your disposal, get some vice grips, clamp onto the nail head and twist it until it breaks, or drive it in flush, or break it off with a cold chisel or hammer claw or hack saw it off or snap it with dikes or fence pliers or....just be a little resourceful.
You need a drill/ bit self tapper screws to fasten the new piece of tin to the frame. Or drill/rivet or something.
Seriously, this is a good start to learning how to fix little stuff that someone else will charge you a bunch of money for.
Ask a neighbor, friend, co worker, someone. You can do this pretty easy.