my selfmade heal pad script dont work?

I believe you are trying to do a cooldown so it wont heal him fast. Well your script is almost correct. Let me fix it:

debounce = false
time = 1 --how long you want to wait (cooldown) before you can heal again

script.Parent.Touched:Connect(function(hit)
    local humanoid = hit.Parent:FindFirstChild("Humanoid")
    if debounce == false then debounce = true --We set the debounce to true for the cooldown
        if humanoid then
            humanoid.Health = humanoid.Health + 25 --You cant just type hum.Health = +25.. it wont work.
            wait(time) --we wait
            debounce = false --debounce = false
        end
    end
end)

Good luck, keep scripting.