Believe it or not, it started with this shitty doodle:
then I used 2d software to color a bit in specific areas (it could be photoshop or krita or whatever you like to shade it a little. I used trial of Portait pro):
Then I feed it to the Deep Dream algorithms ( you can find a bunch of websites or phone apps to do it for free) to iterate couple times feeding it with results over and over. Sometimes I had to remove glitches and unnecessary artefacts.
Eventually I get this:
And this result I pressed with another online tool which find faces and make them 3d:
Phew!
It is a lot of time and work involved anyway.