Thaw safely if frozen, drain and blot very dry. Toss with salt, garlic powder and pepper.
Whisk hot sauce, melted butter and lemon juice in a small bowl.
Heat olive oil in a wide skillet over medium-high until shimmering.
Add shrimp in one layer and cook 1 1/2 to 2 minutes without crowding; work in batches if needed.
Turn and cook 1 to 2 minutes more, until opaque with a loose C shape; large shrimp may reach 145°F.
Remove the skillet from heat, add only enough Buffalo mixture to coat, toss briefly and finish with scallions.