I just finished a duck mount that in the beginning I was very happy with. However I now realize that the positioning of the head isn't that great since it will be hung high on a lofted ceiling. Is there any way to reposition the head without risking the skin?

When you say just finished, how just finished? How long has it dried? Sometimes you can inject the skin with water and reposition, but I have never done it, just been told so.

You should be able to minor adjustments to the head without really hurting anything.