Custom Plugin

I'm creating a wordpress multisite plugin for a new app that's coming out and I'm having trouble getting things to work correctly.

To be more specific, I need to display code above the closing </body> tag of each site. I got everything to work, the only problem is when I created an options page. I added a field to add the account ID number and then network activated the plugin. Everything worked great except that it only updated the current site I was on (which was the admin site). All the other sites didn't have the account ID applied.

How do I set up the options page to place the ID on ALL of the websites, not just one?