You can't go back in the sense that random end-users that visit your site will likely have that cached. In chrome, you can always visit about:net-internals and

You can't go back in the sense that random end-users that visit your site will likely have that cached. In chrome, you can always visit about:net-internals and clear the HSTS cache. Probably not useful for random users, but good to know if you've found yourself locked out of something after messing around with settings.