Can anyone tell me what this is on my son's face?

Kristin • 18 years young⚓️ Mommy to the most amazing lil man.☺️ In love with my best friend.
I don't know what this is but it popped up on my lil boy's face a few days ago. It feels rough. Under his lip is where his lips are chapped. He doesn't act like it hurts but most kids won't when they're sick. This has never happened and I jus wanna know is there anyone out there that this has happened to anyone else's children?