I don't think it's hormone related. My working theory is that it's a combination of physical damage and climate.
I live in cold London, have for my whole life, it's not humid at all here. Whenever I go off to humid locations (e.g recent trip to Mexico) my lips actually heal, and this are the settings I use to my advantage and really go hard with the healing methods. This is the post I've wanted to make for a while but a lack of time and true understanding of what has helped me is stopping me.
I wouldn't say the inside of my lips are sticky. Have you tried keeping them covered all of the time? Recently I haven't been bothered and have just been using regular lip balms.