If you don’t have database access for some reason, you can also use
// use these in your wp-config.php
define( 'WP_HOME', 'http://example.com' );
define( 'WP_SITEURL', 'http://example.com' );
or
// use these in your functions.php
update_option( 'siteurl', 'http://example.com' );
update_option( 'home', 'http://example.com' );
to regain access to your site. You can read more about changing the site urls from the codex, Changing The Site URL