Luckygirl3 my heart goes out to you in what must be an awfully worrying time for you and your family.
In her teens one of my daughters took an overdose too, and like you I worried about the effect on her kidneys and other organs. She is an adult of 30 now and thankfully none of her organs have been affected and she has run several marathons.
I also took several overdoses in my teens and twenties , and again have been fortunate enough not to have had any effects on any of my organs.
I do hope this will be the same for your granddaughter, and that she is able to get the support she needs. I am appalled that CAMHS have offered nothing in the past for her; the three conditions (not sure if that is the best word to use) she is going through must be terribly hard for her to deal with especially in her teens. It sounds very like a desperate cry for help (which I now know was the reason behind my overdoses) and I do hope the professionals involved in her care will help.
You sound like a wonderful, sensitive and intelligent grandparent, and I wish you and all your family the very best for the future.