The tattoos are unique identifying marks, and unless those are removed it doesn't matter if her face is visible or not. Its like taking a photo of the vin number on car. You can identify thats your car by the vin, even though you can't see the rest of it to tell the color, make, model, etc.
Legally, she could pursue it such that the photographer couldn't use them for commercial use, but its gray line regarding portfolio use. Some lawyers argue portfolio use is advertising for the photographer, and thus commercial. Others argue the other way. So its risky to use them anyway because if she decides to pursue it legally, she can find a lawyer that believes portfolio use it commercial, and willing to argue on her behalf. That means court time for both. I personally don't think it would come to that though, but its a risk that needs to be considered.
I wouldn't let her dictate how you process your images unless she was paying you. When a commercial client hires me, I shoot it their way. Typically, they hire me because of my vision, but sometimes they have specific ideas on the end results.
In this case, TFP I believe, she worked with you for your vision, and isn't paying you to do it her way. If she doesn't like them, she doesn't have to use them, and should be more careful in who she works with in the future. But she doesn't have a right to dictate to you how you should process those images. With that said, TFP/s are usually a joint collaboration between the two, with the end result of images both parties can use. So within reason I would try to accommodate her needs as long as it also accommodates mine as well.
Another way to handle this might be to process a few images that you know she will like, and give those to her. If she uses those, then its only fair that you get to use images from the shoot as well. They don't have to be the same ones that she used. It also gives you legal teeth in the sense that it was a TFP, both people got images from the shoot, and her permission was implied from the beginning to allow both parties to use the images for portfolio use.



