From your description, it sounds like you're dealing with more than just naturally thin lips. The fact that you've already had lip filler several times and still feel that the corners of your mouth don't improve suggests that the underlying issue may involve the anatomy of the lips and the muscles around the mouth, rather than simply a lack of volume. Lip filler is excellent for adding fullness and enhancing lip shape, but it has limitations. If the corners of the mouth naturally turn downward or the upper lip has become elongated with age, adding more filler can sometimes make the lips look heavier without creating the lift you're hoping for. In some cases, excessive filler may even make the lips appear less defined. A lip lift is designed to shorten the distance between the nose and the upper lip, allowing more of the pink portion of the upper lip to show. This can create the appearance of fuller lips without relying on additional filler. However, a lip lift primarily affects the upper lip and does not significantly elevate the corners of the mouth. If the corners of the mouth are the main concern, a corner lip lift is a separate surgical procedure that may be more effective than filler alone. Some people also benefit from small amounts of neuromodulator treatment to reduce the downward pull of the muscles around the mouth, although this depends on the individual's anatomy and is usually a subtle adjustment rather than a dramatic change. Because you've noticed a significant change over the past year, it's also worth considering whether there have been changes in your facial volume, dental bite, weight, or overall facial aging, as these can all influence how the lips appear. The most appropriate treatment depends on the cause of the change. If the lips simply lack volume, filler may still be the answer. If the upper lip has lengthened, a lip lift may provide a better result. If the corners are the primary issue, a corner lip lift or other targeted treatments may be more effective than continuing to add filler. Based on your history of multiple filler treatments with limited improvement, I would be cautious about simply adding more filler without first determining why the lips appear smaller. A thoughtful evaluation of your facial anatomy is much more likely to lead to a satisfying, natural-looking result than increasing volume alone.