Nice outcome! As SatanicPenguins said, you can use Curves to make it look better. I tried and that's what I got:

I only duplicated the layer in screen mode and added a new curves layer with these settings:

And also, to get that multiclor effect, you can add a gradient at the top:

And set that layer to Color:

If that stands out too much, you can always desaturate (ctrl + shift + u) the first two layers (your original one and the screen mode one) and decrease the opacity of the gradient layer. You'll get something along these lines:

Just try to combine that effects I say and you'll get something quite similar to the one you posted on the first post

I didn't explain it step by step because I assume you already know how to work with photoshop, layers and blending modes, but if you have any question just ask and I'll try to help.