Healthbar script not working!?!??! making me very salty.

I don't know why this isn't working, it was working before. It doesn't seem to reset after I die. It did like 3 hours ago though.

game.Players.LocalPlayer.Character.Humanoid.Changed:connect(function()
script.Parent.Size = UDim2.new(game.Players.LocalPlayer.Character.Humanoid.Health / game.Players.LocalPlayer.Character.Humanoid.MaxHealth,0,0,20)
script.Parent.TextLabel.Text = math.floor(game.Players.LocalPlayer.Character.Humanoid.Health)
 if game.Players.LocalPlayer.Character.Humanoid.Health < 25 then
    script.Parent.BackgroundColor3 = Color3.new(255,0,255)
 else if game.Players.LocalPlayer.Character.Humanoid.Health > 25 then
    script.Parent.BackgroundColor3 = Color3.new(0, 255, 0)
  end
 end
end)

while true do
    if game.Players.LocalPlayer.Humanoid.Health == 100 then
        script.Parent.Size = UDim2.new(1, 0, 0, 20)
        script.Parent.BackgroundColor3 = Color3.new(0, 255, 0)
    end
   wait()
end