I started with creating a bubble image to use as a brush. Within the circular image I placed a selection from the main image, flipped horz and vert, inverted, and added the shaping highlights to the bubble.
I used this image to define a brush. Then in the brush engine, I set scattering, spacing, size jitter.
Then I added some color highlights to the bubbles with quick paint strokes in several colors. To limit the paint to the bubbles, I linked the color paint layer to the bubble layer.