I have carefully creased the smile lines on a facial morph target by putting loops near each other.  Later when sculpting (smoothing) the cheeks, I find the creases smoothed out. I have tried several times to avoid touching the creases but always have to go back and redo the creases.

My question is: is there some way in Blender 2.45 to lock the vertices you are happy with, from being affected by latter tweaking. The closest thing I have come up with is hiding vertices in Edit mode and using proportional editing. Unfortunately, this is difficult once you make the surrounding area invisible.