I already have very full lips, but I want a more defined Cupid's bow for a more pronounced pity look. What would you recommend?

Yes, you can get a more defined cupid's bow. Technique will be important here, so you will want someone meticulous. I recommend using cannulas with injections.These fillers, (Volbella, Restylane, Juvederm) are good to create a symmetrical and full lip. See an expert. Best, Dr. Emer

pc103.    If the photo of your lips is the one on the far right, your upper lip is already quite full, and I would certainly not add  filler. It appears to be significantly fuller than your lower lip, and filler would increase that discrepancy. Your Cupid's bow is already reasonably well defined, filler may actually blunt it. I recommend that you do nothing. Good luck!