Bethany Joy Lenz put everything she had into writing her new book, Dinner for Vampires. The One Tree Hill alum’s memoir details her time in the Big House Family religious cult while starring on the hit CW series and how she finally escaped the group. However, it was not easy for Lenz, 43, to go back into her memory and relive her experiences. “I’m proud of it. I know how hard I worked on it. I didn’t use a ghostwriter. I wrote that book,” she explained in a recent interview. “It was exhausting, and it was like an information dump. Thank God I had an amazing editor who could help me talk my way…