The OP is not about 4-year-olds who like the taste of Calpol.
Stoppin, you specifically worded your post to pertain to children 12+.
Then you stated that you don't like dishing out paracetamol and that you consider the dose the girl was getting strong.
And that you treat headaches with lying down and water.
Then you get bent out of shape when others point out that it's not a dangerous substance and that doing that is somehow trying to be clever or sad and that people who disagree in such a manner are not constructive and thoughtless.
Not everyone agrees with you. That's the nature of this forum, it's not here to just tell you what you want to hear.
'And Expat...I really would be surprised at the chemist who would sell a 12YO girl a box of Paracetamol...maybe they would, but do you seriously think I would leave her to go and do that??'
12-year-olds are not stupid. If a chemist won't sell it to them, it's not hard to convince someone older at school to buy it for them. Hell, some of them already do this with alcohol.
And if the girl already feels that you're cadgey about giving her paracetemol, well, yes, she may feel she can't come to you for it and needs to get hold of it elsewhere.
When kids feel they can't talk to a particular adult, they don't. They go elsewhere. They don't confide in many adults the way people do when they get older.
Yeah, sure, with your own kids, it's easier to judge, maybe it's dehydration, hunger, etc.
But this isn't your kid, and it may not be the type of headache she's comfortable talking to everyone about - like period or PMT headaches.