mail($row['email'],"Email From Customer","Message:<p> </p>" . $_POST['comment'], $header . 'From: ' $row['email'] . PHP_EOL);
missed out a concatenation!!!!
try this
mail($row['email'],"Email From Customer","Message:<p> </p>" . $_POST['comment'], $header . 'From: ' . $row['email'] . PHP_EOL);