Possible to script to disable the script then enable it?

Sounds like you're looking for a loop. Respectively, the "while" loop. You can use this loop at the beginning of your code, and use the body of it to repeat over and over again. Here's an example:

Here's how it works:

while condition do (Body) end

So, the loop will repeat the code in it's "body" until some false statement is met, or until the loop is broken. Take this example:

while true do
    print'Looping'
end

-- BUT WAIT!
-- Loops without yielding will cause a very unpleasant crash. To fix this, we can use the wait()
-- function. No parameter is needed in this example.

while wait() do -- you can also call functions as a condition.
    print'Looping'
end

Sorry if this wasn't what you're looking for, some example code would help.

You can use a script to disable another script

game.Workspace.Zombie.KillScript.Disabled = true -- Disables the script
wait(0.1)
game.Workspace.Zombie.KillScript.Disabled = false -- Enables it

Loops should help you. Let's say you want it to be an infinite loop, use this;

while true do
wait(0.25) -- You always want a wait, or else your game might crash.
-- Put your code here and it will go on an infinite loop.

Let's say you only want to be killed by the zombie for a certain amount of time, you'd use this;

for i = 1, 50 do  -- replace 50 with how ever many times you want to be killed. Replace 1 to change the starting count... 20-50, 100-1000, ect.
--Code goes here, inside of the loop.
end

Let's say you've written your follow function above and you don't feel like putting it in one of these loops.

Follow()
repeat
-- Put code inside here, it will loop until you die.
until game.Workspace.Player.Died 

I suggest you check out this article about loops.