A smooth doll looks so much nicer and is easier to blush andpaint. You can smooth while you are sculpting polymer clay or after you have baked your doll. Here as some smoothing aides to try:
Smoothing unbaked clay with alcohol or mineral oil
After the sculpt is completed, you can gently wipe larger areas of the unbaked clay with alcohol prep pads (get at a pharmacy) to smooth, remove fingerprints and lift specks of dust. Some doll makers use a mineral oil based products on a brush (such as baby oil, Sculpey Smoothing Oil or hand lotions). There are many products used by doll makers; however, just keep in mind that mineral oil based products and alcohol based products soften the surface of polymer clay so read the ingredients label and use with a light hand and with some caution. Experiment to see if you like what they do.
Smoothing partially baked clay with Sculpey Clay Softener or a mineral oil based based product and extra fine grit sanding pads (such as Magic Eraser) to smooth partially baked clay. The doll is coated with the softener or oil prior to sanding. The clay is very fragile at this stage so be extra cautious.
Smoothing cured clay with Acetone: To finish smoothing your doll, use a Q-tip dipped into acetone (get a hardware store). Acetone dissolves the surface of polymer clay so only use a tiny amount. Don't acetone the face because you could lose the doll's features that you worked so hard to sculpt. If you get too much acetone on the clay, it will leave a whitish layer; you have to immediately wipe it off and redo.