Why isn't my healing pad healing me when there are no errors?

It's not working because your character have full health , this is why don't appear a error message on output.

To solve this problem, I created a block that when touched by the character, it loses life (leaves the character with 1 life always).

script.Parent.Touched:Connect(function(hit)

local h = hit.Parent:FindFirstChild("Humanoid")

if h ~= nil and h.Health > 1 then

h.Health = h.Health - 1

end

end)

And another block with your script :

local db = false
    script.Parent.Touched:Connect(function(hit)
        if hit.Parent:FindFirstChild('Humanoid') then
            if db == false then
                db = true
                if hit.Parent.Humanoid.Health < 100 then
                    hit.Parent.Humanoid.Health = 100
                    wait(2)
                    db = false
                end
            end
        end
    end)

first lose life in the first block and then go to the other, it will heal the character completely.