NumberValue is changed and printed through script but stays is the same in the workspace editor?

local health = script.Parent.Parent.Health.Value
local debounce = false
function onHit()
if debounce == false then
	debounce = true
	health = health - 10
	print (health)
	wait(3)
	debounce = false
	script.Parent:Destroy()
	end
end

script.Parent.Touched:connect(onHit)

I made this script so that it subtracts 10 from the NumberValue (500), changing it to 490. When the number value is printed through the script, the console says 490, as it should. But when I go into the workspace and look at the actual Value of the NumberValue it still says 500. Shouldn't that change too when the part gets hit?