In a medium-size mixing bowl, combine the blue cheese, lemon juice, Worcestershire, hot sauce, salt, and black pepper. Using the back of a fork, mash the mixture together to form a thick paste. Drizzle in the olive oil, stirring continuously with the fork until the mixture is creamy. Add the buttermilk and mix well. Cover and refrigerate for 1 hour. Cut the heads of lettuce into 4 wedges each. Spoon about cup of the dressing over each wedge. Serve immediately.