I'm making bread and a skin formed on the dough...I shaped it into a loaf and have plastic wrap on it now..is it ruined?

A bit philosophically, all bread is ruined. Nothing in bread wanted to be bread. We tell it to become bread and to stop right there.

you can do a couple things to prevent a skin forming in the future.

1) after shaping your loaf, lightly spray oil over the top of your loaf and cover it loosely with plastic wrap until its ready to go into the oven

2) Mimic a proofing box. I have a large plastic tub and a small wire rack with legs. I pour boiled water into a pan, place the wire rack over the pan and then put my loaf on the rack. Then I turn my plastic tub upside down and cover everything. Creates a warm environment with the right amount of humidity to keep the skin from forming. Especially nice in the winter.

Once you've shaped it into a loaf, you're committed. But all is far from lost. Remove the plastic, spray the loaf with some cool water, and you'll be just fine. Let the water sit for about 5 minutes before your put the loaf in the oven, then spritz it one last time before baking. I live in an extremely dry climate, and what you describe isn't at all unusual.

It should be fine but you might want to cut away the "skin" and discard it.