How I did it:
First I tried to take a picture that would symmetrical to make it easier for me. Then I looked which graphs would fit the best to my features. For my took for example used many reflected, extended or compressed parabolas. For my nose i used circles with restriction and for my cheek bones I used the cosine function. But the original cosine function is horizontically, so I needed to turn it and make it vertically by changing x ans y in the function. To move it 7.5 to the right I did (x-7.5) it gets translated horizontically. Then I put a minus in front of the cosine function to change the direction of the bulge. And then I expanded it a lot to make it less wavy.