Preheat oven to 350℉. In a large skillet over medium heat, melt butter. Add garlic and cook until fragrant, 1 minute, then add flour and whisk until combined and golden, 1 minute more. Stir in milk, parsley, and a pinch of red pepper flakes and let thicken, 2 to 3 minutes. Add wine, ½ cup mozzarella, and Parmesan, and season with salt and pepper. Add shrimp and cook until pink, about 2 minutes more. Stir in lemon juice.