Betta Fish: Help with my baby betta

I wish I had better pics of her when she was still a baby but sadly I don’t. (First pic was at about 4weeks).
She’s probably about four months old now, seems to be fully grown. I housed her with my baby panda mollies from day one so she is used to being in a community tank, she might even think she’s a mollie lol.
Anyway, a couple days ago I noticed her lower lip looked a little more dark pink than before. I assumed it was her coloring changing/getting more intense but I’m not entirely sure. It hasn’t gotten worse, doesn’t appear swollen, and her behavior is the same.
Does anyone think this is the start of an infection?
I don’t want to remove her from the tank and medicate if it’s unnecessary..

(My water parameters are 0 ammonia, 0 nitrites, 6-7 nitrates).
(90g planted tank).
(I do anywhere from a 25%-40% water change weekly).
(I just fed freeze dried brine shrimp when I took the pic of her, my water isn’t dirty).
(Since day one her gills have looked reddish, and she’s always had a few dark spots in between her scales on both sides of her body).
(She’s starting to develop pearlescent coloring around gills).