I must be confused or this is just a really simple problem. If you have a loop, let's say a foreach and the array is paragraphs you want in your email, just do something like this:
$message = "Hello, Jack!\n\n";
foreach ($paragraphs as $paragraph)
{
$message .= $paragraph . "\n\n";
}
$message .= "Sincerely, Joe\n";
mail(...);