Why does your skin swell when bottle stuck to lip?

When a bottle is stuck to your lip, the pressure and suction can restrict blood flow and cause localized swelling due to fluid accumulation in the tissues. Additionally, the skin can become irritated or inflamed from the constant pressure, leading to further swelling. This reaction is a protective response of the body to injury or irritation. If the bottle is removed, the swelling usually subsides as blood flow normalizes and the tissue recovers.