You’re nowhere near the amount of polygons it would take to slow Blender down, so I don’t think that’s the issue. Give Sculptris a try for sure to see if you like it, but I don’t think it’ll solve this particular problem. Getting a tablet would make a much bigger difference than switching programs.
I think the main issue is that you’re worrying about eyelids way too early. Start from the very large forms and work your way down to the details. Don’t sculpt a mouth or nose until the shape of the head is excellent. It’s actually impossible to sculpt good eyelids if the surrounding anatomy (cheekbones, brow, nose, etc…) is off.
To get a better understanding of the face, draw a few first. I highly recommend taking these courses before jumping back into sculpting:
https://cgcookie.com/course/facial-features
https://cgcookie.com/tutorial/portrait-painting
https://cgcookie.com/tutorial/warrior-tutorial-timelapse
After that, this course will help you with sculpting faces:
https://cgcookie.com/course/art-of-sculpting
Sorry to be so blunt, but you’ve got to walk before you run.
