When gods give their blessings in the form of skills, say, heal, it is possible to become an apprentice. However, when the blessing disappears after completing the circle, the apprentice status remains even though the red skill bar goes back to zero skill. My question is whether the apprentice status guarantees the skill or does it go back to no skill?
Thank you.

I believe you keep the apprentice bonus only, not the actual benefits from the skill being high enough to correctly get the bonus.

So, no skill. It is still useful though because you keep the modifiers which can be pretty good.