New to Headshots - some advice?

Hi all... first post here in the group.
I had actually posted some shots earlier today... but I realized that I didn't discuss posting them online with the subject before I posted them... so I took them down until I can get her to give me the okay.

I'm a pretty new photographer (only shooting DSLR since November '14) and I am taking a class working on portrait and headshot studio photography. One of my dear friends was kind enough to bring her daughter to class for us to use as a model. She's done some acting work and already has a set of headshots from an actual pro... but I want to deliver some professional quality shots to them since they modeled for us and put up with a group of students trying to figure out how to direct the shoot.
After going through my images I think I have a few shots of sufficient quality to fit the bill... and I showed them to her mom... and she agrees. But they need some more post-processing. I did a little exposure and contrast work... for the overall image quality... I'm okay with that... but there needs to be a little more "fine detail" adjustments. Some skin softening... a bra-strap cleanup... a little acne, stuff like that. I know acting headshots should be very minimally edited... I just don't know how to do that stuff. I've fiddled with it in Lightroom CC...but I usually overdo it and screw up the shot.

Any thoughts/ recommendations on Retouching services for this? Is it worth sending them out to a pro? How much does it typically cost per image?