So I walking down the hallway of school and I saw this guy coming in the opposite direction of me. When I saw him, I noticed he kept looking at me (my face in particular) and kept his eyes on me even while I was passing by him. Why did he keep on looking at me when he does not even know me?

What are your ages/

He may think you are silly looking, he may think you are hot. He may wonder who you are, or thinks he knew you.

100s of reasons,

He doesn't have to know you to look at you, and only he knows why. What do you do when he looks at you? How old are you?

Maybe your lipstick was crooked.

It could mean a lot of things.
Do you look back at him?