you could just try removing them from the front end where the content is being displayed - this will then remove the <p> tags for that specific content for that page regardless of what is happening in the backend
Depending on whether you are using mysql or mysqli, you could do it this way:
if mysql
<?php echo(str_replace("<p>","</p>"), "", $row_RSname['ColumnName'])); ?>
if mysqli
<?php echo str_replace(array("<p>","</p>"), "",($RSname->getColumnVal("ColumnName"))); ?>
hope this helps
Jamie