How to fix an uneven chin? I have had two genioplasties. (photo)

In the one photo that you provide your chin looks symmetrical. I can see some strain of the mentalis muscle that can be treated with some Botox. Good luck

Dear calboo,it wold be the best to consult a board-certified plastic surgeon as a photo does not reveal enough information. Generally speaking, an implant exchange or dermal fillers might be required to fix your chin asymmetry. Daniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery 
Member, Am. Society of Plastic Surgery

Hello
You pose a very good question and a difficult issue to address.  Without a formal exam, it is difficult to tell from the one photo exactly what is happening with the chin.  As with any secondary or tertiary surgery to redo the genioplasty, we have to take into account the muscle and skin over the chin. It appears that some of the muscle from the one view may have been positioned too high and towards the right. This needs to be addressed in addition to the bone if it is also asymmetric (it is difficult to tell with the one photo). 
Make sure you address these concerns with your surgeon.