Welcome mate,
The Jawline is one I do without stretching the skin, too much. I do a north to south pass and then aim for a flat surface and go across the grain ear to mouth. Sometimes need a little bit of blade buffing just at the base of jay next to the ear lobe as my hair tends to grow in various direction there, let it grow for a day or two and look at which direction it is growing in, it could be that it has a different direction to what you think. Other than that it is just persevere and try different things, you'll get there.
I have more problem with the base of my neck, swap you :lol:
Enjoy the forum.