invincible for 3 seconds?

I made a script for my custom health bar to make my player invincible for 3 seconds... didn't work, no output errors. Anyone know whats wrong? script:

local Plr = game.Players.LocalPlayer
local Char = Plr.Character
script.Parent.Changed:connect(function(val)

if script.Parent.Value >0 then
local Health = script.Parent.Value
for index, child in pairs(Char:GetChildren()) do
if child:IsA("Part") then
while wait(3) do	
if val ~= Health then
script.Parent.Value = Health
child.Transparency = 0
wait(0.35)
child.Transparency = 1
elseif val == Health then	
child.Transparency = 0
wait(0.35)
child.Transparency = 1
wait() -- anti freeze	
end	
end
chilf.Transparency = 1
end
end
end
end)

This will work I fixed it

local Plr = game.Players.LocalPlayer
local Char = Plr.Character
script.Parent.Changed:connect(function(val)

if script.Parent.Value >0 then
local Health = script.Parent
for index, child in pairs(Char:GetChildren()) do
if child:IsA("Part") then
while wait(3) do    
if val ~= Health.Value then
script.Parent.Value = Health.Value
child.Transparency = 0
wait(0.35)
child.Transparency = 1
elseif val == Health.Value then   
child.Transparency = 0
wait(0.35)
child.Transparency = 1
wait() -- anti freeze   
end 
end
child.Transparency = 1
end
end
end
end)

If it's a local script just add a wait(2) at the very start of the script and it should work.