Man, don't know how your script is coded, but if it's PHP maybe the following piece of code will be useful:
Code:
<?php
$end = $description[strlen($description) - 1];
$end != "." ? $description .= "." : 1;
?>
Assuming that the name of the variable is $description, this code will put a period at the end, in case the last char is not a period.