Any lotions that contain petroleum based products can ruin your suit.
DON'T use talc or other powders in the situation you describe. If you're wet it will simply turn into a paste.
I personally don't prefer a skin, as the material will allow water to leach up through the skin, losing some of the seal that you're looking for to stay warm in cooler waters.
Baby shampoo is great, but my personal favorite is KY. You only need it on forearms and portions of the legs where the suit is hanging up.
It is non-toxic and since it is water soluble it rinses away.
Anyway, lots of input in this thread. Try some of them.