Scars can "stabilize" or "improve in appearance" , but once there do nit actually shrink. Think of a surgical scar on your body (I have a lot to choose from) - some formed keloids, or overgrowth of fibrous tissue and actually look worse over time. Others smmoth out as fatty tissue grows in, but don't actually go away - there is always a slight dip or ridge, an area that does not tan, or other indication.
Of course, we can't see what's in our lungs, but my doc showed me scars on my last CT. Looked the same as 3 years ago
Sue