16 months post-op & breathing became pretty bad a few months ago, what is inside my nose?

Hello, Although it is hard to say from a photo, based on your description and what can be seen, it is possible that the "lateral crura" part of the lower cartilages is recurring back into the nose. This is a form of nasal valve obstruction. Turbinates and other types of obstruction require an in-person exam to evaluate. For now, breath right strips can help during exercise and sleep, but make sure to bring this up to your surgeon, or visit with another qualified rhinoplasty surgeon. Good luck.