Maxime, did you ever get a culture done? I can't remember. I believe my issue started and worsened with physical and emotional trauma. It could be that the trauma invites opportunistic bacteria and fungi which causes the hyperactive inflammatory response.
Some people such as seb, and myself possibly as well, may have been reinfecting themselves over and over with the same microbes each time they were close to ending the inflammatory response and slowing the peeling rate. I will get my results for a third swab soon and can confirm or deny that MRSA is still present on my lips.
Might be worth getting a swab done even if you have done it in the past.