bleeding is the first worry, but often, blood vessels have been cut, so plugging the hole won't save you from such wounds, and infection is highly likely to kill you later, too, absent modern medical care. Plus, if it's shtf, being NOT at the top of your game, even for a few days, is likely to be fatal, and gunshot wounds often take MONTHS to heal from and often leave you maimed, or at least, not 100%.