How can I fix my slanted and off-center lips? (photos)

It's most likely too soon to tell what your final results will be. You may still have swelling, which can be asymmetrical, and last 1-2 weeks after lip injections. The fat doesn't usually migrate. If you are unhappy after a few weeks, you can always obtain better symmetry with additional fillers. See an expert. Best, Dr. Emer

It is hard to appreciate the fullness below the lip on the left.  The left lip itself is fuller on the left than the right so some filler would equalize that.  As for the fullness you see, the fat may have been placed below the lip intentionally or accidentally.  It is not likely that it migrated - it gets trapped when placed.  Muscle irregularities by the chin can be treated well with botox.  If your lip appears off center, it likely is - there are no perfectly symmetric faces and it reflects more your bony skull asymmetries than a lip problem.  Chasing perfect symmetry and having surgery to make it more centered would be a mistake.Dr. Zenn