Managed By The Highlander by Rebecca Preston

When she’s thrown back in time to 16th century Scotland, Cassidy finds herself assisting a supernatural being and falling in love with handsome William…
Former Hollywood agent and babysitter to the stars Cassidy Keene is used to dealing with spoiled brats and being alone, since finding a real relationship is impossible. But when a drunken star drives them into a palm tree at a hundred miles an hour, she wakes in the waters of Loch Ness—hundreds of years in the past—only the cheerful, drunken idiot with her is not the star she was babysitting.
Docks quartermaster William Grant keeps things shipshape for the fishermen and Watchmen of the Keep, so he’s less than enthused when a half-drowned future woman and a completely blitzed Sidhe crawl up onto his docks. He doesn’t have time to babysitter either of them, but the Sidhe turns out to the Fae King’s son, and he wants William to show him the Grant lands.
Uniquely qualified to assist William with this request, and she offers to help manage the flighty Sidhe noble. But there are witch hunters in the area, ones who care not if you are a witch or Sidhe and are ready to burn either at the stake, along with those who assist and protect them.