Yes, I've noticed this too. Even after the outward signs of a pimple are gone I still have a hard spot under the skin, with not much outward sign of anything being there. All of mine have done that so far and afterwards have left a pretty noticeable scar. I can't explain what it is, I have never experienced it before I started taking accutane and attribute it to the massive break out I have experienced because of the accutane.

I've experienced this both before and during accutane. It's annoying and tends to leaves more of a scar than a typical pimple.