trying to find brush

[default3g50rh75fwxn]

I don't know what brushed I used to mix my two colors. I cannot seem to find it. It was very speciifc, and it was used with the smudge tool. Attached is the image with with the mixed colors. 

[S_Gans]

It may now be too late, but when this happens, and you haven't created a preset, you can go back in your history to the brush state, and look at your brush settings. I'm afraid that unless someone on here has used the same brush, with the same smudge, and the same look, it'll likely be hard for anyone to suggest what you might have used. 
One thing I've learned to do, from experiences like this, is to be very specific with my layer naming - and also creating presets of brushes that I might love, that were unique. 
I hope someone else recognizes it for you.

[Nancy OShea]

No doubt a soft, round, Mixer Brush Tools with reduced Opacity & Flow.  And possibly a Blend mode of Dissolve.

Click and hold the brush icon on your PS Toolbar for more options.  If you don't see it, click the 3 dots icon to customize your Toolbar.  See screenshot.