For the first few days or weeks, when it would have been most prominent in the news, she was living with Mami. No idea whether she ever went outside except at night to hunt witches. If she intended to let the world know she was alive, she would have done it then, so she may have been deliberately laying low.
After that she was homeless and avoiding human contact. She'd be in the places homeless people usually are: alleyways, dark corner, under overpasses, places where she wouldn't be seen, places no one owns or cares enough to patrol regularly, keeping her hood up to make her face harder to see and cover her distinctive hair. People try to avoid looking at the homeless, and when they do notice them they remember the trimmings instead of the faces: the dirty and torn clothes, the multiple bags, the smell, what disgusting bodily function they were performing in public, what incoherent thing they were screaming. It won't be long before she doesn't look anything like whatever photographs of her survived the fire, anyway: living on the street prematurely ages people. Not that it matters, because within a month the news cycle has moved on and the public has forgotten what the other Sakura kid looked like.
I'm sorry to say that it's hardly uncommon for a teenager to go missing and never be found, or for a homless girl to end up living on the streets and vanish from the eyes of society. I pay attention to the homeless because it's my job to. Most people just tune them out. They're invisible.
