My fireball damage script isn't doing any damage?

So as the title implies, I'm trying to create a damage script for my fireball, however, when fired no damage is done to a humanoid. Here is my script:

script.Parent.Touched:connect(function(hit)
	if hit.Parent:FindFirstChild("Humanoid")~= nil then
		hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - 20
		script.Parent:remove()
	end
end)

Respond ASAP, Thanks!

Firstly, never use deprecated functions, read this to know more about deprecated functions and instances. Secondly you should use Humanoid:TakeDamage(20) as its more efficient and less messy then hit.Parent.Humanoid.Heath = hit.Parent.Humanoid.Health - 20.

Here is the fixed code (I tested this in studio so I know it works)

script.Parent.Touched:Connect(function(hit)
    if hit.Parent:FindFirstChild("Humanoid")~= nil then
        hit.Parent.Humanoid:TakeDamage(20)
        script.Parent:Destroy()
    end
end)

First create a RemoteEvent in Workspace and name it "Fired" Then implement this in the script:

game.Workspace.Fired.OnServerEvent:Connect(function(Player) -- Finds the RemoteEvent
	local AlreadyTouched = false
	local Character = Player.Character or Player.CharacterAdded:wait() -- Finds a Player
	local Fireball = script.Parent -- Finds the Fireball you created 
	
	Fireball.Touched:Connect(function(Hit)
			local Humanoid = Hit.Parent:FindFirstChild("Humanoid") --Finds the Player that has "Humanoid"
			
			if Humanoid == nil then return end
			
			if AlreadyTouched == false then
				AlreadyTouched = true -- If it touches, then it'll activate this
				local debris = game:GetService("Debris")
					if Humanoid then 
						local creatorTag = Instance.new("ObjectValue") -- Creates a tag like a tool
						creatorTag.Value = Player
						creatorTag.Name = "creator"
						creatorTag.Parent = Humanoid
						debris:AddItem(creatorTag, 1)
					end;
				if Humanoid.Parent == Character then
					Humanoid.Health = Humanoid.Health - 0
				else
					Humanoid.Health = Humanoid.Health - Humanoid.MaxHealth/2 -- Change the damage
					Fireball:Destroy() -- If it hits the player, it'll disappear (You can delete this if you want to)
				end
			end
	end)
end)