Purple nipple

Angel

My daughter is almost 8 months old and I breastfeed and pump. I rarely feed her directly from the left though and mostly pump that side because she prefers the right and the left nipple is the one that is purple but I have no pain in it. Also, I'm 21 years old if that helps. The only thing I can find on purple nipples is cancer or pregnancy. Is there any other reason that a nipple can be purple that I didn't see?