Lip splitting

My sons upper lip for the past few months has been splitting almost everyday

He breast feeds as soon as he wakes up, drinks milk with breakfast and water for the rest of the day and sommeeetimes juice. And I put chapstick every night but it for the most part comes off with tossing and turning

When he was born his top lip would always peel too so I’m not sure if it’s a big lip thing

I got smaller lips and his dad has big lips but we aren’t sure if that happen to him when he was little.

Help please 😣

In the picture he has chapstick on but he has one split to the right