Yes, you use a wired mouse if the wireless mouse doesn't work... unless you are telekinetic or are NEO and can mentally enter the machine code world.
You also must make sure you installed Bootcamp correctly, because you need to update your Apple software within Windows, as it downloads Bluetooth drivers that autoconnect the keyboards and mice. After that, if it still isn't recognized you have to pair the devices from the Bluetooth menu, and in my experience you need to do that 2 or 3 times before it takes. (first won't see it, jiggle the mouse until it sees it, pair it... repeat until it properly saves the settings).
But most of the time, in XP 64-bit anyway, it recognizes it immediately without any installation.