If you're looking to stop your upper lip from growing back, there are a few things you can do. First, you can try waxing it. This will remove the hair from the root, and it will take longer for it to grow back. You can also try threading, which is a similar process to waxing but uses a thread instead of wax. If you're not a fan of either of those methods, you can always shave your upper lip. Just be careful not to shave too close to the skin, as this can cause irritation.