If you are around your friends (which is not recommended), he may think that you're doing it just for attention if you open your eyes and look at them. If you open your eyes but you are alone, he may think you are scared or turned off. He may also think that you are looking at someone/something behind him, and the last thing you want him to do is stop kissing you so he can turn around to shoo them away.
If he is pleased, great. Keep going. Lean back in and kiss him again, take some initiative. If he is angry, then end the situation--no one would like someone to keep on trying to kiss that person if they're uncomfortable. You should be mature enough to step back if you need to..
If he liked the kiss you'll most likely kiss again and again. Look at his lips and he will get the signal you want more.....