I created the big hair in this image using the wonderful brushes it is possible to create in Metabrush. The hair makes the image, as well as the surprised expression on her face.
I started with this photo from the Sktchy app.
In iColorama, I applied Style/Tonelab preset 4 at medium opacity, Style/Coherence preset 1 at medium opacity, and Style/Flow preset 1 at medium opacity, to smooth the image.
I opened the image in the Metabrush app. On a new layer, in Caustic mode, using a Water brush, I brushed over the image. In brush settings I used spacing at the middle setting, position variance .75, rotation variance .65, rotation and size dynamics 1.00, and shadow and structure at the minimum. I painted with a medium to large sized, 60% opacity brush.
Still in Metabrush, on another new layer, I painted on this big hair. I used Paint mode and the Brok 7 brush. In brush settings, I set spacing at the minimum setting, position variance at .67, rotation variance at .46, rotation dynamics at 0.0 (middle), size dynamics at .77, opacity dynamics at .59, and structure and shadow at the maximum.
I used this photo from Pixabay, a source of copyright-free images, as brush image for the above Metabrush brush. I chose a texture photo with colors similar to her hair, and some highlights.
In iColorama, using Effect/Blend, in several blend steps, I blended various versions of her together, each time trying different blending modes and slider settings, including the Lightness slider under Set. The versions I used in these blend steps included the above two Metabrush outputs, the pre-Metabrush image, and various outputs of Effect/Blend with different blend modes and slider settings.
I used Effect/Blur preset 17 at low opacity, with a brush mask for the face and parts of the hair near the face, painted with a large soft brush. The result is that it gets slightly blurry towards the outer edges of her hair.
I used Adjust/High preset 1 at low opacity, to emphasize the highlights and a for a bit of sharpness.
Using Brush/Paint and a medium opacity small brush, I painted in catchlights in the eyes. Then I smoothed the catchlights using Style/Coherence and an inverted brush mask with a very small brush. I used Form/Warp to enlarge the head, in particular, widening it.
As final touches, I applied Preset/Border preset 7 for a whimsical squarish border. I used Effect/Raise and Effect/Sharpen on the eyes, both at medium opacity, with an inverted brush mask and a small brush.