Hi Tracy, I may need to get some more details to troubleshoot your issue. Are you able to see the page in SiteBuilder, and just having trouble editing it? Or, are you not able to see the page in SiteBuilder? If it's the latter, which is common, it might be that the page just did not open when you re-lauched the SiteBuilder application. You can re-open the page by clicking the Open icon on the top toolbar as shown. Then just scroll down, and select the page you wish to edit.
After you click the Open icon, you will get a pop-up like shown below. Just select the page name you wish to edit.