User blog comment:The Nemesisx/The fate of Noob Saibot/@comment-13038232-20120519123436

I think of 3 possibilities:

1. He was indeed killed

2. As you said, an opposite effect turning him back to his human form

3. A worse effect, turning him in a more...hellish form, more like an Oni.

But since everything is acceptable in the Mortal Kombat Universe, at least one of this possibilities could be true.