6 months post-op - What could cause an uneven soft lump after facial fat graft? (Photos)

At six months your results have been final for a while and there is no longer any swelling.
Facial fat transfer is tricky business and delivering consistent quality results is very difficult. The number of people who need secondary or revision procedures is quite high especially when working with surgeons who do not have exceptional amounts of skill and experience.
Either follow up with your surgeon or have formal second opinion in person consultations.
Best,
Mats Hagstrom MD