We did BB gun wars back in the day. The rule was you could only pump your gun once...which of course no one followed. Most of us wore science lab goggles that we "borrowed" from our HS (I still need to return those).
During that "war" we had
A BB go under a kids fingernail, we had to pop it off to get it out
A BB go into a kids tongue. It was by best friend, I tried digging it out with a knife, it did not work. He had to go to the hospital.
A BB went into a kids eyelid. Hospital trip as well, ended up totally fine.