Why won't my custom health bar work?

local Gui = script.Parent
local Fill = Gui.Health.Frame
local char = script.Parent.Parent.Parent.Character
hum = char.Humanoid
local Player = game.Players.LocalPlayer
repeat wait() until Player.Character
local Character = Player.Character
local Health = hum.Health
local HealthMax = hum.MaxHealth
function updateBarAndText()
    Fill:TweenSize(UDim2.new((Health/HealthMax),0,1,0), Enum.EasingDirection.InOut, Enum.EasingStyle.Linear, .1, true)
end

I was experimenting with tweening to make a health bar but it does not work. I don't see any errors