Solved Chance when pvping

I need help making a chance feature So when u hit players you get a chance to earn +1 health

I tried didn't

PHP:

  $chance = mt_rand(1, 100);
   switch($chance) {

          case 15:

  $event->getEntity()->setHealth($event->getEntity()->getHealth() - 1);


work

 

PHP:

    public function onEntityDamage(EntityDamageEvent $ev) {
        $damager  = $ev->getDamager();
        $chance = mt_rand(1,2);
        switch($chance){
            case 1:
            $damager->setHealth($damager->getHealth() + 1);
            break;
            case 2:
            $damager->sendMessage("");

this is a 50/50 tho. you could just add more cases which are sendMessage to decrease the chance of +1 health. This is the wrong way to do things but it would still work