Preheat an outdoor grill for medium heat and lightly oil the grate.
Whisk the hot sauce and olive oil together in a separate bowl. Brush the flesh side of each pear half evenly with the mixture; place on preheated grill with the skin side on the grill. Stir the blue cheese and butter together in a small bowl; scoop even amounts of the cheese mixture into the cavity of each pear half.
Grill the pears on the preheated grill until soft, 10 to 15 minutes.