She "complained of a wrinkle when she smiled" which is why this extremely unnecessary treatment was carried out. That she complained at all about lines when she smiled is indicative of psychological illness at her age. Whether this can be considered tantamount to abuse is dependent on how she came to develop these notions of essential cosmetic perfection based on an impossible "perfect female". The actual injections of botox were carried out by her mother whom I am lead to believe is a trained beautician. Whatever I think of this as a substantial and worthwhile career, I think they're at least trained to properly administer BTX-A as a cosmetic therapy. She would presumably understand what she was doing well enough to do the procedure, even if she lacked the reasoning and rationale to acknowledge it as superfluous and psychologically damaging. I don't believe she was putting her child at any substantial physiological risk of botulinium poisoning though; if I'm right in saying she's qualified to do it.
She shouldn't have done it, but what she did wasn't evil just deeply misguided.
Removing her from her mother may hurt her as much as the pageants did though. She could feasibly stay with her mother provided she was given regular visits from a social worker, court ordered to stop partaking in beauty pageants, and both of them scheduled to receive counselling; the mother for her dangerous delusions about worth based on cosmetic intangible perfection and the daughter so she can grow up free of her mothers delusions before they're too deeply ingrained in who she will become.
I cannot imagine how much it hurts both of them to be separated and I question whether it was necessary. She was incredibly stupid and deluded, but there are stupid deluded people having children all over the world everyday. The pageants should be illegal, they're abusive and destructive.
If there is any evidence of further abuse (negative reinforcement for failure or otherwise) she should definitely be taken from her and put into care.
I'm as surprised as you are I didn't choose yes unconditionally, but being in care isn't a positive experience for most children, many never finding a foster home or adoption. If there's any way she could stay with her family, I believe this would be overall a more positive outcome for everyone.