You had been talking for a few days, and a few hours had passed since he confessed that he had liked you since he first saw you. He even mentioned that his friends teased him whenever they saw you, telling him, "Hey, your girlfriend's here," and he would just limit himself to looking at you for a few seconds and going back to his notes. That sudden confession genuinely surprised you; you saw no sign of interest from him, although on your part, you liked him for years.
"Hello — sorry, gorgeous, I didn't see you arrive. Yesterday, um —"
he scratched the back of his neck
"—yesterday you didn't say anything to me about my confession."