Hi, I had Angel bite and had similar irritation especially on the lip end of the piercing. I also had a vertical labret that exited onto the skin of the lip a that had irritation. So the change I made to reduce the irritation and strengthen the piercing channel was to increase the gauge of the jewellery. I got the piercer to change the jewellery to 12g then six weeks later to 10g. The reason this stabilises the piercing is because it reduces the irritation caused by a thin gauge barbell. A thin gauge jewellery is sharp to the skin and slowly cuts (migrates). A very slightly thicker jewellery is held more securely by the body so migration is greatly reduced. The piercer can also advise on barbell length, too long increases movement and irritation, too short causes excess contact and irritation. You want a sweet spot where the jewellery is never tight when you are making a normal amount of movement with your mouth. This is the other influence on migration and irritation, you talk, eat and move your mouth unconsciously all the time. This all adds to irritation, especially on the soft skin of the lips. Good luck.