Are piercings still open even though collapsed?

[Groves]

I know that people pierce their blues with lots of things.

Bamboo skewers, thermometer probes, phillips screwdrivers, etc.

I know that the purpose of the piercing is allowing oxygen into the interior to develop bluing there.

I know that sometimes you need to re-pierce (the same holes) to keep them open.

What I want to know is what correctly pierced holes look like. Mine seem to close immediately no matter what the size, but maybe they're only closing most of the way? Do your piercings stay round and open?

[T-Bird]

I've got a small 1 gal. "stilton" working now that I smoothed on 7-4-10 (the object of my other post) I pierced it with a 1/8 in bamboo skewer on 7-18-10, the holes are still open. I have been piercing with a different brand of bamboo skewer and a thermometer probe both of which are slightly smaller in diameter and have felt like I needed to reopen the holes based on the way they looked on other cheeses. If this cheese turns out, I'm staying with the larger holes.