The Archemist explains that her current condition is due to old wounds and that it's her punishment from Atom for angering him.
She reveals that she once worked as a doctor in Far Harbor, but then fell for a pious man. Those from Far Harbor who didn't agree to their union chased them away. The man she fell for has abandoned them since.
Despite the dialogue hinting at disfigurement, when one removes her surgical mask and garments her face and body appear unscathed with the exception of the Child of Atom markings on her face, her narrowed and blackened eyes and her face being noticeably hollower than average.
Although the Children of Atom worship radiation, it is possible to let the Archemist heal the player character's radiation. The Children of Atom call this 'scouring' and it is done out of necessity (for not every Child is blessed with immunity against the negative effect of radiation) or out of religious penitence: 'Scour oneself and embrace the Glow anew.'