The smallest X/Y detail the printer can print is 0.4mm (with the current nozzle). Anything smaller than that is ignored. To get finer, you have to follow brent113’s suggestion of a smaller nozzle.
FWIW, I regularly print with 0.04mm layer heights (using Cura). It does take a long time, but I don’t mind. The terraced steps on the cheek and shoulder will be much smaller.
The flat background does look a little off. I like to see a smoother surface than that. I think if you calibrate your E-Steps, you’ll be happier with the results. I recommend new printers go through xchrisd’s 3D Print Walk Through. It starts out very easy, and gets to some semi-technical sections. Feel free to skip anything that feels overwhelming, and come back to it later when you feel ready.