Nothing you can do with those lights really. They are devoid of detail. The outer glow hardly sharpens but a glow should be soft anyway. What you really should do with this (IMHO) is open it in Bridge and bring it into Camera Raw.
I decreased exposure just a bit, brought temperature into the blue, increased the recovery a lot, increased the black, the fill light, the contrast, the clarity, and the vibrance, mostly in minimum to moderate degrees.
Then importantly I sharpened the whole images, zeroing in on the faces, real tight. I didn't do much with the other sliders. Tried luminance but it didn't help much.
Then I opened it in PS. It comes in as a smart object. If not, make it one. Select the lights and as little else of the trees as possible and nothing else in the photo. Go to filter>sharpen>unsharp mask or smart sharpen and give the trees a tweak. Then take a soft brush at 30 to 50% opacity and brush around the edges of the sharpening and on branches that look too crisp -- do this on the filter mask.
I think the sharpening itself helps since, unless you want to go into every lightbulb and add some imagery, you aren't going to sharpen a totally white area.
Nice kids!
I made the photo here about half size. It's huge! But you can make the changes and keep it that size if you want.
Did you by any chance increase the resolution in Photoshop?
Looking at this loaded up here, it looks like I went too far with the blue filter. Maybe it needs no temp adjustment after all. Or perhaps the kids have to be isolated from the background and color balanced a bit more. They also appear to need a bit more contrast on their faces which are noisy. This doesn't strike me as an originally 300 or 240 res photo . . .