sorry to resurrect an old post. You don't need to add a metabox, just amend the code that displays the comments - the actual code you will need to replace will depend on which theme you are using.

However, please note that you should avoid comparing the comment e-mail address with the current logged-in user e-mail address as suggested above as a registered user can change their email address. This does not then change the email address used on existing comments so only comments made after their email address was changed would be displayed.

Probably better to compare user-IDs:

if ($comment->user_id == $current_user->ID

You don't need to add a metabox, just amend the code that displays the comments - the actual code you will need to replace will depend on which theme you are using.

However, please note that you should avoid comparing the comment e-mail address with the current logged-in user e-mail address as suggested above as a registered user can change their email address. This does not then change the email address used on existing comments so only comments made after their email address was changed would be displayed.

Probably better to compare user-IDs:

if ($comment->user_id == $current_user->ID