If you leave it on 24/7 then your lips will heal underneath the barrier. In my experience with using this product, you should never remove the barrier until your lips are fully healed. If you take it off too soon, then the good skin will be exposed to air and will die very quickly. Then you'll have to start this all over again.
Yes, you have to apply this on completely raw lips. It just makes your lips look chapped or very dry but after a week you'll see the lines on the corners of your bottom lip getting deeper & the natural color coming back. That's how you'll know your lips are healing.
To be clear, this isn't a quick management technique to suppress the symptoms. This is totally different. Either you use it to heal your lips & be determined or don't use it at all.
Maybe this won't cure everyone's ec because everyone's condition is different but from what I've seen, this is most likely going to cure MY ec.