In his article, “The Limitations of Pure Skeptical Theism,” Paul Draper argues that skeptical theism can’t be applied to Humean arguments from evil (like Draper’s own argument). To be sure, Draper repeats some of the points that he has made before. Nevertheless, it seems that (many) skeptical theists needed a refresher.
As a reminder, skeptical theism claims, “…we should be skeptical of our ability to discern God’s reasons for acting or refraining from acting in any particular instance.” 
In addition, Humean arguments from evil are arguments that focus on comparing multiple hypotheses in their ability to explain the existence of evil.
Drapers’ main objection to skeptical theism is that it doesn’t really change anything with respect to our epistemic situation. It’s true that, for all we know, God has a morally sufficient reason for allowing various evils in the world; however, it’s also true that, for all we know, God doesn’t have morally sufficient reason for allowing various evils in the world. In fact, for all we know, God is able to accomplish all she wants without all the evil in the world. 
One of the most popular skeptical theists is Michael Bergmann. His version of skeptical theism asserts that our knowledge of goods and evils is not representative of all the goods and evils that there really are. Hence, just because we can’t see a good reason why God allows evil, that doesn’t mean there isn’t a good reason. Bergmann claims that skeptical theism could apply to arguments from evil like Draper’s argument. That’s because, according to Bergmann, Draper’s argument relies on assessing the probability of there existing various evils given the hypothesis of classical theism, but skeptical theism denies that we can do this.
Draper’s response is that Bergmann is confusing objective probability with epistemic probability. Even if, according to Draper, we are unable to determine the objective probability of there being various evils given theism, that does not entail that we can’t assign a high epistemic probability that various evils would not exist given theism.  Hence, Draper-style arguments from evil don’t rely on the assumption that we are in a position to see that God doesn’t have a good reason for allowing the existence of evil.
It doesn’t seem that hard to see why someone would/should have a high confidence level that we wouldn’t see the types of evil that we observe if theism were true; the whole reason there is a problem of evil in the first place is because, prima facie, there does seem to be a tension between the existence of God and the existence of evil!
Perhaps there is a version of skeptical theism that can be applied to Humean arguments from evil like Paul Draper’s argument. For now, however, it appears that the verdict is that skeptical theism is useless when applied to certain arguments from evil. Or, skeptical theism alone can’t undermine particular arguments from evil. 
 Draper, Paul (2013). The Limitations of Pure Skeptical Theism. Res Philosophica 90 (1):97-111.
 I find the claims, “The existence of evil doesn’t count as any evidence against God,” and,”Evil doesn’t give anyone prima facie justification to believe in God’s nonexistence,” to be incredible. Literally, I don’t find such claims to be credible.