In a large bowl, add thinly sliced pork, lemongrass, shallot, garlic, white sugar, honey, fish sauce, soy sauce, oyster sauce, oil, salt, and pepper. Thoroughly mix together.
Cover bowl with plastic wrap and let marinade for 2 hours, up to overnight, mixing halfway through. If marinating for more than 2 hours, place in fridge but let come to room temperature before cooking.
Soak skewers in water for at least 20 minutes. Preheat oven to 375°F and line a baking sheet with foil.
Thread pork onto skewers, leaving a little space between each one and double threading when possible. To double thread, pierce skewer through one end of the pork, twist the meat, and pierce the skewer through the other end of the pork as well. Evenly spread the skewers out onto the baking sheet.
Roast in oven for 10-15 minutes (internal temp should be around 160°F), then broil for 10 minutes until lightly charred. Keep an eye on the pork while it's broiling because the sugar can easily burn. Let cool slightly before serving.
To make the scallion oil, add green onion and ½ tbsp oil into a bowl. Microwave in 15 second intervals, stirring each time, until green onion is bright green and lightly wilted (it took me 30 seconds total). Brush onto pork and serve alongside Nước chấm dipping sauce.
