The image definitely needs some work. Color balance may be somewhat subjective, but it is far less so when dealing with faces. Aside from this photo having too much cyan and green in the face (check the INFO palette), there is nowhere near a white point. The boys forehead, near that point of hair, read something like C-29, M-22, Y-23, which is much closer to a cadaver than a small, happy boy.
Here's what you can do:
First, open a levels adjustment layer and set the white point for each RGB color. That will help with the initial color balance and give you a white point, which you do not now have, which is why it looks muddy.
Second, go into a curves adj. layer and add a bit of yellow and magenta into the midtones of their respective blue and green channels.
That should get you very close to what, I think, you are looking for. But as was said already, you might want to think about starting over from the original file. It's a good learning process.
Important noteIn cases like this, the INFO palette can be invaluable. I set my palette up with one side reading K (gray) and the other CMYK. I used CMYK rather than RGB as it's easier for me to think in terms of 0-100% as opposed to RGB's 0-255. If you try this setup, a
rough starting point for Caucasian faces is somewhere in the neighborhood of C-12, M-25, Y-30. The gray (K) can read zero for faces.
This is not perfect by any stretch of the imagination, Shirley, but it's much closer to what I think you are looking for. I used the above two adjustment layers I mentioned as well as a photo filter adjustment layer with a warm tone set to 10%.