Post-breast reduction: Why do I have black nipples and one swollen/tender breast? (Photos)

Hi there. Thanks in advance for any help. I am 2 weeks post op, from a 34G/H, now hopefully a small 34C. have two concerns: 1. The black color on my nipples? Especially the right one, really dark. 2. Today my lower left breast had some irritation, and slight dark discoloration toward the bottom. The side toward my armpit is especially sore, tender, and firm in comparison to the other breast. I’m 2 days from my period so I wanna hope it’s hormones but why only one breast?