A few weeks ago I turned my wipers on in the rain and they were fine.. then all of a sudden they started to hit the bottom of the front window at the base of the hood and on the upswing the wiper would go all the way over and hit the plastic piece and it wont stop. It has a very wide arc and no limits to where it needs to stop on the windshield. What could this be?

you might want to adjust the wipers. i dont know how that happened, but you want to check it out before you damage your hood.

Is this for bolt wiper? See how high the wiper goes then check the nut.