The inside of my lips

First of all.. I just realized this year that other people deal with this on many different levels. I only suffer in one area with this disorder and it's my lips. This started back in elementary school & I became aware of it shortly thereafter, so I started keeping it behind closed doors. I’ve never discussed this w/ 1 single soul. I think it’s odd and I don’t understand it. I have been doing this for 18 years (give or take). This is accompanied with cheek biting & moving my tongue over the damaged area, which leads to more damage. Why would I inflict this upon myself? I consider myself a happy, successful individual & I deal with stress, like everyone, but if I think back to when this all started, I didn’t even fathom any type of stress was until maybe junior high. Why was I picking before then? I love to kiss & it just does NOT make sense to me b/c I will avoid kissing if I’m healing. I’ve been told that I have a beautiful smile, but I’m sabotaging this. In any event, the few things that help are acrylic nails & fresh finger nail paint to stop picking, but it’s only temporary. Regardless, I can’t stop the biting. Since I entered my career full time 4 years ago, I have felt stress at an intense degree and it’s become worse and more frequent. As much as I believed before that this will stop when I have a family of my own, I’m started to realize that it won’t just happen on its own & it may even get worse!? I don’t want to do this anymore & I still think it’s so very strange & embarrassing. Help.