OP I can empathise, and I think you’ve been given a bit of a hard time here.
My DDs nursery went through a phase of being obsessed with putting Sudocrem on her bits, every nappy change. There was nothing wrong with her. At most, there was sometimes a slight bit of redness that came with sitting in a wee nappy for too long (on their watch, mind!). But nothing that wouldn’t go away after a simple wipe with a wet flannel. I didn’t agree with slathering her delicate bits with Sudocrem constantly, but they were obsessed with her needing cream for her “rash”. We’d send it in, they’d lose it and sternly ask us for more. You have to remember that nurseries are generally underfunded, workers are underpaid, they’re just doing their best.
I can also empathise with the hair - I’ve had one with tight curls that hated being brushed. Keep it short (bob length), keep trying different hair brushes (we’ve found a simple paddle brush to be gentlest), trial and error. We pop the front in clips or a top knot and leave the rest a loose bob. Trying to wrestle a nursery-aged childs hair into a full ponytail or plaits is a fools errand.
To answer your original question, all you can do is meet with nursery and cooperate. Turn up looking well-kempt yourself, and with a friendly and cooperative disposition (not argumentative). Take their advice on board. It will be fine.
Unless you are doing something which indicates actual neglect (sending her in dirty/smelly clothes, leaving a sore rash untreated, never bathing her and sending her in smelly, etc), you will be fine.