There's no built-in "return to my account" link — Login As simply issues you that customer's own login token and puts you in their session exactly as they'd see it, with no special impersonation banner or exit button. To get back, log out and sign back in with your own SuperAdmin credentials. If you need to keep your own admin session open at the same time, open the customer link in a private/incognito window instead of your normal one.