Melt the butter in a large skillet over medium heat. Add the garlic; cook and stir for about 30 seconds. Add shrimp; cook until they start to turn pink, about 3 minutes. Pour in the tequila and lime juice and season with salt and chili powder. Simmer until the liquid has evaporated, about 3 more minutes. Pour shrimps on a plate and garnish with cilantro. Serve with lime wedges.