lol that would be the least of your worries
ive never been to a heavy metal concert but as far as i know you dont get fucked up unless you want to. people keep the violence contained to the mosh pits, and theres kind of an etiquitte, you dont really take cheap shots on people or bully people, otherwise you get fucked up. my friends brother in law told me a story of how he was at a slayer concert once and this huge like 350 pound dude slammed this tiny girl to the ground, and like 10 people all started slamming into him at nearly the same time, he ended up on the ground trying to crawl away as people stomped around on him and shit, he ended up losing some teeth and had a broken arm cause he violated the etiquette