Combine buttermilk, sour cream, apple cider vinegar, parsley, chives and garlic in a bowl; stir well and season with salt and pepper. Chill for 30 minutes.
Toss lettuce, carrots, celery and scallions with buttermilk dressing in a large bowl. Place in serving bowl.
Warm a large skillet over medium-high heat. Add oil and butter. When butter sizzles, add shrimp and cook, stirring, until opaque, about 4 minutes. Add buffalo-wing sauce, stir to coat shrimp and cook 1 minute longer. Pour shrimp and sauce over salad.