The answer is that the concealment cannot make what certainly exists cease to exist. No matter how many flaws and defects you can think of, His existence, blessed be His Name, is intrinsically necessary. If so, it is impossible to conceive of any deficiencies except after the initial axiom that God certainly exists. All you can say is that He is concealed and that this is why the defects emerged, but His existence is a certainty.
If so, even within the concealment itself, one thing remains enduring: His existence and the existence of His perfection – for they are one and the same. This is what sustains the world and prevents it from being destroyed, for any other existence besides Him is inconceivable. But God is perfect goodness. If so, it is inconceivable that there is any evil that is not in some way subject to perfect good.