I have experienced face-morphing several times, both sober and on hallucinogenic drugs. Doing it sober is much more pleasant for me, less eyes dripping out of your face and that kind of thing.
This is an optical illusion achieved when you are sitting in a dim/dark room with a light source behind you. When you look in to a mirror, you will see your face change. For me, I usually have to focus on one part of my face and the rest will change. When I blink or my eyes move I see my normal face again.
From my experience I would think it is more a trick of the brain than a spirit making contact (I don't think I'd like a spirit playing on my face anyway!). However, that does not mean it cannot be a powerful or spiritual experience.
You could try the exercise again. This time however, command or ask yourself to show certain types of faces. I have requested to see all of the following, with interesting (and telling) results: My male (animus) aspect, shadow self, ancestors, true self, myself as an old woman, and possible variations of myself (if I were born with different genetics). You could try requesting to see your soul mate, your greatest fear, or anything else. It is a fun exercise. I have also seen people of various ethnicities, typically Native American, Spanish, and what I suppose I would call Greek, as well as people of different genders and ages. Their facial structure is usually unique as well.
The three I remember the most are my 'shadow self', animus, and the old lady. They were all very vivid. The trick for me is to keep your eyes very still and focused without blinking, otherwise the illusion is ruined.
I did this for an hour or so one day. As I went deeper and deeper in to it, the mirror appeared to vibrate very rapidly, like it was being violently shaken. This happened a few times as I watched myself. Afterwords, for a few days after that, I would get the sensation that I was being shaken very quickly or that everything was vibrating around me. It went away though.
Of course, I do not want to be pedantic, but be sure to protect yourself if you are doing mirror exercises. It is my opinion that intense focus an connecting with a mirror can open up a portal. If it were me I would do something to protect the mirror itself and then shield myself while I do the exercise. No need to risk something coming through.