@rainy-dazed If you get a chance, you should do it.
People always appreciate being genuine(In my experience), unless they express otherwise. And I know I would be pleasantly surprised if someone came up to me and told me my face looked nice.
And unless this person is a jerk, they'll probably react positively and kindly. But it's up to you, and if you feel like you don't want to, then don't!