DS has red rashy lips - what has caused it?

[Spagblog]

DS looks like he is wearing lipstick, dark red lipliner caused by some kind of rash...They seem sore and a little swollen.
The on call GP seems to write it off as cold sores, but I don't see how it could be.
None of us get them, and no one else he is in contact with has them.

sounds as if it could be an allergic reaction - has he eaten anything new?

I don't think so...

Could it be an allergy? is it scabby or just red and swollen? Does it come on after eating any particular kind of food or using a particular soap/suncream on his face?

It could be coldsores, if you look up close at it, can you see blisters, even tiny ones? he would only have had to have some small contact with the virus on a towel at someone elses house, or perhaps a toy gnawed on by a child with an active sore. But it doesn't sound normal for it to be all round his lips, poor little sod.

If it doesn't look blistery then I would try him on a child strength antihistamine to see if that calms it down (if it is an allergic reaction to something) or perhaps something soothing and safe like sudocrem.

has he used any lip balm or cream that he could have reacted to?

Still mysterious, today all the skin on his lips has started peeling.
He seems okay in himself although has been falling and tripping and crying a lot today - probably not connected.