Poison on Skeletons/zombies

I have this code:
For zombies and skeletons is poision like a regeneration so I added regeneration But it still not working.
Other mobs are working

Code:

                if(e.getEntityType().equals(EntityType.ZOMBIE) || (e.getEntityType().equals(EntityType.SKELETON))){
                    p.sendMessage("zombie");
                    el.addPotionEffect(new PotionEffect(PotionEffectType.REGENERATION,5*20, 2,true));
               
                }else{
                    p.sendMessage("not zombie");
                    el.addPotionEffect(new PotionEffect(PotionEffectType.POISON,5*20, 2,true));
               

                   
                }

 

You're checking if the entity is a LivingEntity right ? Post whole method if you can

 

Code:

 @EventHandler
     public void onEntityDamage(EntityDamageByEntityEvent e){
         if(!(e.getDamager()instanceof Player))return;
         if(!(e.getEntity()instanceof LivingEntity))return;
         Player p = (Player)e.getDamager();
        

         if (p.getItemInHand() == null
                 || (!(p.getItemInHand().getType() == Material.DIAMOND_SWORD
                         || p.getItemInHand().getType() == Material.IRON_SWORD
                         || p.getItemInHand().getType() == Material.GOLD_SWORD
                         || p.getItemInHand().getType() == Material.WOOD_SWORD)))
             return;
        
         if (!p.getItemInHand().getItemMeta().hasLore()
                && !p.getItemInHand().hasItemMeta())
            return;
        if (p.getItemInHand().getItemMeta().getLore()
                .contains(ChatColor.GRAY + "Poison IV")) {
            LivingEntity el = (LivingEntity)e.getEntity();
            int randomint = (int) (Math.random() * 100);
            if (randomint < 99) {
               
                if(e.getEntityType().equals(EntityType.ZOMBIE) || (e.getEntityType().equals(EntityType.SKELETON))){
                    p.sendMessage("zombie");
                    el.addPotionEffect(new PotionEffect(PotionEffectType.REGENERATION,5*20, 2,false));
               
                }else{
                    p.sendMessage("not zombie");
                    el.addPotionEffect(new PotionEffect(PotionEffectType.POISON,5*20, 2,false));
               

                   
                }
                

Whole class

So there is no way to poison them? If no i can use reapiting task I guess.

Edit:
Anyone know how much is poison doing dmg?

<Edit by mrCookieSlime: Merged posts. Please don't double post. There is an Edit Button right next to the Date.>