Yes, I have done this many times. Usually I just see myself with no defects or abnormalities, but there are those occasional times where something else will appear. Once I saw a reflection of myself when I was 7 years old. Another time I was horribly deformed. One of my shoulders appeared to be coming out my ear, and my mouth had drooped down to my stomach!
I remember laughing at that. It was a nightmare, but I was trying to change the mood a little. There was this one time when I noticed a mirror on the back of a door in a room that in reality contains no mirror. When I got close to it, I looked into my reflection's eyes. I noticed my eyes were no longer hazel, but silver. I watched as tiny specks of gold formed around my iris, then gathered together in my iris turning it gold. (It didn't change my vision.) That was pretty cool to watch. I think what you see really depends on your intentions, your mind set and emotions, and the dream itself. So anything can happen, really.