If you feel uncomfortable when someone is looking it's fine to call this person out and tell them to stop.

Teenage guys and their raging hormones make me very uncomfortable.

I agree with Benni90er - you have every right to speak up and say something.

When that happens to me, I get out a tissue and pretend to blow my nose. I make all kinds of noises. That tends to get them "out of the mood" real fast.
And welcome to Teen Hut!

I personally feel uncomfortable if I know that I have made anyone of any age uncomfortable by my actions or words, but much rather have someone speak up as I won't know that is how they are feeling if I don't and so won't be able to change if I am not told. This is why I try to make sure I either hold eye contact or look over girls shoulders to avoid unknowingly have my eyes stop and blankly stare at inappropriate spots.
I also feel that his reaction was very unprofessional and just a very bad way to react. We should be showing respect for one another not make someone else's discomfort a joke.
So yes, please, please do speak up if anyone ever makes you feel uncomfortable

From what you wrote no one can answer that question. He stared at you, maybe because he likes you, maybe because he doesn't.

No, you should always call out someone if they are behaving badly like that

Staring at your lips and his pupils dilated?
I think you’re reading too much into it

Yeah if it was nips not lips maybe
But lips is fine
Some cultures don’t like looking people in the eye, it’s disrespectful to them

When pupils dilate, it is often a sign of sexual arousal.

I’ve never heard of pupils dilating because of arousal, from drugs sure

More than likely you gave him a boner.

Me thinks the OP was a troll.

NO WAI