How to stop a while loop that's in a function from a module script?

I have the function in the module script:

local module = {}

function module.StartUp(blox)
	local on = blox.TurnedOn
	local gui = blox.Screen.StartUp
	local rotate = gui.Frame.ImageLabel
	local y = 1 
	local button = blox.onoff
	rotate.Rotation = 0
	
if on.Value == false then
		on.Value = true
		button.Material = Enum.Material.Neon
		gui.Enabled = true
		wait(2)
		rotate.Visible = true
		y = 1
			while y < 1000 do
				y = y + 1
				rotate.Rotation = y
				if on.Value == false then
					break
				end
				wait(.01)
			end
else
		button.Material = Enum.Material.SmoothPlastic
		on.Value = false
		gui.Enabled = false
		rotate.Visible = false
	end
end

return module

When I click the button that triggers it once it works just fine but if I spam it the while function mixes up with the other while functions that haven't been stopped in the background thus accelerating the ImageLabel's rotation. How can I fix this?