To see how your follow-up email campaigns have performed, go to your Launches tab (1), then click Campaign History (2) from the top menu.   Here you can see all the results of your campaigns, including survey campaigns, and any custom follow-up campaigns you may run.  The columns provide the summary stats regarding the number of emails sent, as well as the number of campaign emails opened (3).  By clicking on the name of your campaign, you can view the contacts who were sent your campaign.   

After viewing your campaign recipients, click the link to Return to Campaign History.