I read the first episode and since these comments already started there, I guess I know what you are talking about. I don’t think that the author intended this to be offensive or racist, because we are actually talking about the MC’s best friend and they love each other. It’s very common in real life that friends tease each other. The author probably added this because she thought it was funny it’s not, but I don’t think she meant any harm. I personally wouldn’t call the dialogue anti black, the MC was just honest about not liking her BF’s new hairstyle, which I think was just a pretty unfortunate choice from the author’s side that she probably didn’t even realize.
I agree with @brittanysmith, I personally wouldn’t report this, but it might be worth to ask the author in fanmail to rewrite these dialogues. If she gets the same feedback from more people, it’s more likely that she will change it.