Is it normal for my areola to turn pink after a nipple graft? (photo)

This to me looks like secondary healing after partial necrosis of the areola. For this reason I would use an anitbacterial cream until it is completely healed.

Thanks for your question and photo.
When the nipple and areola are transferred as a free skin graft it is very common for people with dark skin to loose some of the pigmentation and color.  I always make it a point to tell people before surgery that this may happen.  As long as the underlying skin is healthy this is rarely a problem as the color will usually return.  It can be a slow process and take several months.  In the rare case where I have a patient not regain all the normal color, we will tatoo any remaining small pink areas to make it match the surrounding tissue.  
Best wishes.