I created an output page, and then selected the attributes to show on that output page, but the new output page is showing up on other products where it shouldn't be.

[Darth Moxy]

I'm assuming it's this checkbox on the output page that you used?

If that's the case, that checkbox resets all the attributes on all products to go on that output page. The best way to fix that is to delete the new output page and recreate it - this time DO NOT check that box, but only put attributes and parts from that single product on the output page.