But if her bites are all like the one you describe, it sounds more like a male's soft mating courtship, harem-gathering type of biting. BTW, male igs are known to be not always very nice when they want to drive or mate with a female.
Do you remember how your vet determined her sex? If she is a neutered female you might see the healed remains of disturbed scales along the incision line.
Anyway, neutering a male or a female does not prevent this kind of behavior. It's been tried a lot by desperate iguana owners, normally with males. I've read about the results of it through the years but I can't remember any reports of improvement.
It's not totally uncommon for adult females to start this behavior. If she isn't easily distracted by treats, then I think you should carry a small towel to throw over the front half of her body. Some owners take to carrying a broom which as I remember is a good way to turn the front of their bodies away from the attack position, and to push igs away or block them when they try to herd you.
If it becomes unbearable, we all would suggest limiting her access to you, because serious injuries can happen. A scar to your leg or arm is one thing, but a scar to your cornea or your face must be avoided in case she decides one day to ramp up her behavior. She really could suddenly decide to run up your cloths to get a bite on your face. It's happened to me.
But I really wish to know if all her bites are soft.