There isn't a problem but it's getting a little bit weird since its basicallyt the same hair with slightly different facial features. I think if you want to continue using that type of hair, you should at least change the color or the skin color or something of that sort, get it? And all of your heads look similar because they share the same hair, skin color, shading, and basic mapping, lol try something new like a monster because the human stuff is becoming too common. It was amazing when i first saw it but now that you made three almost identical heads its kind of getting "boring". I still love your style but i think it would fit more on monsters and sort.