I'll second the concentration on the lips and chin. As for 'old growth' on my neck, we're working up from the Adam's apple. There's a patch of blue that stands out, but now it's just the part of the neck just underneath the jaw, so it's not as noticeable.
Every other session, we go back and clear lips and chin then work out to cheeks and other high-visibility areas, the next session we tackle the old growth. This lets me shave the area that's not going to get treated, and letting the lips and chin grow out is hardly noticeable now.
When I do go out all hairy, I act as if nothing is the matter, and STILL get ma'am'ed.
Chin DOWN...and all that--
Karen