When you experiment with this, the placement of the candle you will find works best if it is off to the side. But play around with it and put it where you feel it best brings stuff out. Personally, the less intense the light is on your face, the more the imagination will take off with what is coming up.
I use to do this meditation alot a number of years ago. I remember the first few times I tried it there was some unbelievable images that were pretty shocking. After posting this, I pulled out an old mirror and lit a candle and tried it again. Seems my basement is pretty cleared out because I didn't see much that looked grotesque as I remember. An interesting thing happens when you have come to the point when you are clean. And that is that if you keep staring at your image, soon you will find that you are not there at all. The mirror becomes empty! Have a look and see it for yourself.