How to correct my uneven lip and potential cost?

Your asymmetry is only apparent when you smile, so correction must be done with great care because your lips are quite attractive when in repose. I recommend correction with a filler like Juvederm Ultra plus by an experienced injector very conservatively because over correction will cause another asymmetry. If you like the result, then you can consider fat transfer for a longer lasting result. Seek out a board certified plastic surgeon or dermatologist with lots of experience treating lips. Good luck!

Juvederm is the most superior injectable for your lips.  Please make sure you go to a reputable office to get your lips injected.  Juvederm can last you 6 months to 1 year in your lips.  I expect you will only need one syringe to get your desired outcome.  Good luck, hope this helps.

I would suggest meeting with  a board certified plastic surgeon or dermatologist and try conservative filling with Juvederm. Initially, just ask to make your lips more even.

Thank you for your question and for sharing your photographs.  Based on your photographs, you appear to have some baseline asymmetry that is accentuated by smiling.  I would suggest a conservative lip augmentation with a small amount of Juvederm.  Please be sure to see an expert injector for an in-person consultation to fully address your concerns and discuss your goals and expectations in order to determine the best treatment plan.  Best wishes!