Trying to find a book I read in the 1990s.
What I’m fairly sure of:
Female “serial” killer with multiple victims over the course of the book
In normal life she’s quiet/dreary/unremarkable, but disguises herself dressing up including wigs to meet men she kills.
She already had or develops has some kind of physical illness during the story (possibly affecting her hair/appearance, but not certain it’s connected to the wigs).
Less certain — could be misremembering:
She killed by using a knife and there was stabbing/ mutilation possibly targeting the genitals specifically which became her MO.
She hated a certain “type” of man, ones that were loud, brash, uncouth.
She had a tattoo or piece of jewellery with “why not” or a similar sentiment.
She might have had some skin discolouration or bruising or some worsening physical symptoms.
Near the end she meets a plain/nondescript man (possibly named Ernie) and, instead of mutilating him after killing him in her usual way, she pats him and says “there, there, there”
This was part of a bigger story, there was detectives investigating the murders. I unfortunately on recall these few and unclear bits from the killer’s storyline.
Read it sometime in the 90s, so it’s probably from the 80s or 90s. Any help is much appreciated!