DD (8) had a little trouble recently. I got some Vagisil wet wipes (chamomile and something) to soothe it and clean it and a Mr Bump bruise pack just to make her feel a bit cooler. I also bought some cystitis drink, in case that was causing a problem but by next day she was fine, so it wasn't necessary.
If shes still sore tomorrow I'd be tempted to go see a doc, but then I'm a bit of a worry wart about this kind of thing,
My dd (2.3) is complaining her 'bits are sore' and they do look very red - she waits til she's got a nappy on at sleep time to poo and it spreads everywhere. I don't know how much delving to do to get the bits out, she hates having it cleaned, so I put sudocreme on but I'm worried leaving poo in that area will do more harm. No one tells you how to clean girly bits!
My daughter has this a lot. She suffers from a condition called Vulvovaginitus. She get incredibly sore and itchty and it hurts when she wees. Went to the docs so many times before being refered to a consultant who diagnosed it straight away. He said GPs just don't have a great understanding of it and give canestan which actually makes the soreness worse. He prescribed an oestrogen cream which did the trick. Oh and down below was very smelly too. If these ring alarm bells I would see a your GP and mention this as the consultant said 1 in 3 girls before puberty age suffer with this.
I'd recommend Sudocrem all the time. My DD is 10 now and has intermittently suffered from sore botty. Often there's been no apparent reason for it but it's usually when she's been on a school/brownie trip and not showered every day.
A nice cool bath, sudocrem overnight, and Bob's your uncle. It's fab stuff!