Hi CariLeigh
You picked a really difficult for your 1st restore and by now everyone will want to warn you not to trust what looks easy in the gallery. Some will even go so far to warn you that we do a bait and switch.
The real warning sign that this will be a really tricky one to color correct is seeing all of the florescent lights in the background. I have a feeling that this photo had a greenish cast when it was new and the camera's white balance got fooled by the florescent lights. Because of that I disagree with Johnboy when he said:
I would suggest going for good skin tone and let the rest of the photo fall where it may. Looks like some florescent lights in the background that are not that important.
I'm not sure how Johnboy’s version came out with Levels since he forgot to post. GK went with Curves and after trying different solutions: I decided to color correct in Lab. Don’t panic as there are many ways to go about restoring. The reason I did not want to correct in either a Levels or Curves in RGB was that I felt the colors would be all over the place. That is why you were able to have parts of your photo looking good and then had troubles with the rest. I also think it pays to try to balance all of the photo rather than just “going for good skin tone and letting the rest of the photo fall where it may.”
I changed my color mode to Lab and then duplicated my layer and then clicked on the Channels. Lab has the top layer that shows color, the lightness channel, and the a channel (red/blue), and the b channel (yellow/green). I clicked on the Lightness channel which will give you an image in black/white (luminosity) and them went up to Image Adjustments>Shadow Highlights. I brought the shadow slider to the left to the point that I like the tone better. Then I went back and used the short cut key to do a Curves Adjustment in Lab (Ctrl M) . Below is what I did.



After doing that, I flatten and changed the mode back to RGB.

Even then, this version leaves a lot to be desired (not counting all the spots remaining), because it is rather anemic looking and leaning to the cool side. The one thing I forgot is what looks like a spinal cord on your far right; I use a gradient mask to conceal it as I found it very distracting. I believe it is showing the photos being printing and dropping down the chute.
Like GK said, don't get discouraged and you should give yourself a big pat on the back for trying this one. Also, there are different ways to approach each photo. The people are the most important part in this photo and if you can tone down the green, you will headed in the right direction. Good luck and keep us posted.
Margie