When you register a username account you provide an email address and that email address becomes your unique Identifier. When you are logged in under that username account and register a blog it's registered to that username account and associated email address.
You have two separate email address settings at WordPress.com.
Blog notifications for the admin (like comment moderation, Likes, new subscriptions, etc) are sent to the email address at Settings -> General in the Dashboard.
Personal notifications (like comments on your post, subscription emails, and upgrade renewals) are sent to the email address at Users -> Personal Settings in the Dashboard.
See also > Issues Changing your E-mail Address > http://en.support.wordpress.com/email-address/#issues-changing-your-e-mail-address
The My Blogs section of your Dashboard lists the WordPress.com blogs that you can contribute to and/or edit. http://en.support.wordpress.com/my-blogs/
Clicking this link should display all your blogs registered under the same username, including the hidden ones: https://dashboard.wordpress.com/wp-admin/index.php?page=my-blogs&show=hidden
If you do not see the blog here http://en.support.wordpress.com/my-blogs/ then
follow this guide > http://en.support.wordpress.com/my-blogs/#my-blogs-dashboard-visibility