As mentioned, it'll take a while for him to warm up.
One thing I've done with my pigs since late January is feeding my pigs veggies with my arm(s) in the cage. Each time I feed them I sit beside the cage and reach my arms into the cage. For them to receive food, they must come up to me and eat from my hands. Every time they hear the veggie bag they immediately run up to the side of the cage and eagerly wheek. They sniff the air and stand up on two feet as I lower my arm into the cage.
You have to take it one step at a time. Sit beside the cage, talk to your little pig. He will learn to recognize and anticipate your voice. Hold your hand in the cage. Don't try to touch him with your hand in the cage for a week or so. Just set it next to him as he munches on his food. You can occasionally wiggle a finger towards him, but he may flee. I try to think of arms as snakes. Are arm is the body and our hand is the head- Who knows if guinea pigs see them as snakes, but what I do know is they think it's a giant, scary monster out to hurt them. By keeping your hand next to him, he will learn to trust you. Eventually, you can touch him as he eats. If he runs away or backs off, leave him alone. Try again later. One of my pigs allows me to pet her entire body as she eats, my other one is still iffy about it but is getting better.
While holding him, bribe him with veggies. If he jumps out of your lap and runs away from you, keep food near or on your lap. He'll have to gain courage to come back and eat it from you, thus learning, "Hey, this big scary monster ain't trying to kill me! Maybe I can trust him/her!"