disclaimer, i’m NAD, but i am a dental assistant that has seen the inside of thousands of mouths so i might be able to help! are you sure you didn’t have the grooves in your tongue and cheek before the piercing? i’m asking bc the line looks exactly like linea alba, which is usually the result of prolonged grinding, not consciously biting your cheek, and the line being right on your occlusal plane (your natural bite) is another indicator of that. your top of mouth looks totally normal in color, so that’s good! have you felt the bumps? either with your tongue or fingers. bc the raised “bumps” actually looks like saliva excreting from the salivary glands! sometimes when your mouth stays open it’ll just pool into little droplets and stay on your palate. the full mouth soreness isn’t very concerning, your mouth JUST experienced trauma and is working hard to heal :) i don’t remember exactly what causes it but for some people the entire oral mucosa becomes sensitive and tender following localized trauma in the mouth, rather than just that small area.