How do I allow remote access to mysql using xampp?

Just make sure that your mysql is binding to a socket on 0.0.0.0 and you should be able to connect to that socket. I guess the default is for mysql to bind to 127.0.0.1, which, of course, is hard to reach from the outside.

EDIT: The MySQL configuration file should be in .\xampp\mysql\bin\my.ini. You need to find the bind-address parameter and change it to 0.0.0.0.

Everyone on your network should then be able to connect that MySQL instance. Of course, that may include people who better shouldn't do that. But as long as there is a password for each mysql user and the instance is not facing the internet, there is not much to worry about.

If not found, add it.

bind-address=0.0.0.0 under mysqld

See it http://www.afella.org/mysql/my.ini