HA fillers normally last about 6 - 12 months. I have seen some people where the filler last longer, with no problems, even up to 3 years. If there are no issues with the filler, just leave it alone and at some point it is likely to dissolve. Occasionally there is a small part of the filler that seems to last, with the rest breaking down, which is probably due to a capsule around the filler. If this is causing a problem it can be broken down with Hyalase. Rarely there is a thickening of the tissue, rather than residual filler, which may be more difficult to break down. My recommendation would be to get a review with your Doctor, so that you can both decide what is best for you.