DD sat in stinging nettles today and now has a very itchy, lumpy bottom

[Spookler1]

........what can I put on her bum to relieve her of her uncomfortable itching?

Oh no!
(How did she manage to get stung on her bum?!)
Can you find a dock leaf?
My colleague apparently was having a wee round the back of her stable on saturday not seeing the nettles sorry but I had to pmsl

give her a dose of piriton, and [put her in a coolish bath with bicarb in it.

believe it or not vinegar, my dd fell in ome nettles and was literally covered from neck to toe, it was pretty horrific and she was hysterical. A good friend of mine was here and suggested soaking some flannels in vinegar, and honestly it worked a treat.

She was playing in the garden and went to get her ball out of the hedge. She stumbled and landed on her bottom, straight onto a pile of them.

OUCH! Next time, get in there with the dock leaves quick. They should be easy enough to find as they grow naturally close to nettles.

2nd the suggestion of vinegar though.

you could give her some antihistamine such as clarytin or boots own make, or a topical cream for insect bites such as anthisan or similar. you don't say how old she is, so you would have to check labels etc. If she is old enough you could try piriton. calomine lotion can help a bit, but it is a bit messy. HTH

vinegar is good for wasp stings too, bicarb good for bee stings.

I've just found a bottle of calamine lotion in the cupboard left over from when dds had chickenpox. Have put some of that on and she doesn't seem to be complaining any more.

arrr your poor little girl