Morgan,
  My nursing toddler leaves six teeth marks, too, on the top of the nipple.  I
am not pregnant, so other than the odd look of teeth marks it isn't
troublesome to me.  It did help, however, when my son first started to get top
teeth, to re-evaluate how I was holding him and how "front-on" to the breast
he was.  Toddlers do tend to nurse in acrobatic positions if we let them, and
a little gentle guidance might be appropriate since mom is in pain.

Lisa Jones, LLLL in Wellington FL
(whose oldest is ALSO named Morgan, and she was four years old on December 4th
-and she will tell you that whether you want to know or not!)