Photos of your breasts would make anwering this question much easier. Any answers without actually analyzing your photos are purely speculation.
Correcting a nipple that is "too high" can be a difficult problem to fix, but the fact that this nipple is too high must first be differentiated from asymmetry that has resulted from the opposite nipple being "too low."
Only photos and a physical exam can make these distinctions. Don't fret. The solution to correcting your asymmetry may be simpler than you think.
The timing of revision surgery is also important. How far out you are from surgery timewise is an important factor to consider, as the shape and appearance of the breasts can continue to change dramatically over time.
Go see your plastic surgeon or have him refer you to a colleague who can evaluate you and help you with your concerns.
