After reviewing your code there are a couple of things you need to change depending on where the meta content is being held.
If you try
$meta = get_post_meta( get_the_ID(), 'custom_text', TRUE );
echo 'The meta content is: ' . $meta;`
That should give you the appropriate meta.
You are calling this function on the page content, so unless the meta content is being held there nothing will be output.
Hope that helps!