In a previous posts, Fran asked about getting cracks in the finished head. After about 300 figures now, I have found that it is important to keep your clay covered with plastic after sculpting the face; or the rest of the figure for that matter. Polymer clay loses oils as it sits out in the open. The longer it sits around, the more crumbly and cracked the clay will become. I use a polymer clay skull under my faces which sucks even more oils out of the clay if it sits around too long.
The repair will show but they can be covered well with washes of color. This head was sculpted out of ProSculpt Caucasian clay and repaired with ProSculpt Baby clay so there will always be a difference in the color. Again, for this piece it will only add to the feel of the finished piece but for a pretty lady, I would start from scratch.
Hope this helps. Have a great day!