How to hide a Fivestar field in a comment when the user didn't vote?
You could try an approach like this (untested) but may work

/**
 * Implements hook_comment_view
 */
function hiderating_comment_view($comment) {
  if($flag = flag_get_flag('reaction_on_own')){
    // Debug comment to find field to hide, check dblog / watchdog
    debug($comment);
    if (!$flag-&gt;is_flagged($comment-&gt;cid)){
      unset($comment-&gt;field_stars);
    }
  }
}