It actually isn’t permanently changed. When paper factories make paper, they push unsettled paper through high pressure steam rollers to smooth it out. When you get the paper wet, the paper unsets itself and goes back to its rough original texture. You can push it back through a steam roller to smooth it out again, and that is partly what happens when we recycle paper.
Motrin/ibuprofen (and related drugs like Voltaren/diclofenac and Aleve/naproxen) decrease fever by lowering levels of chemicals that tell our brain to raise our body temperature. These chemicals are called prostaglandins and thromboxane.
I’m not sure how acetaminophen does it, but it’s through a different mechanism. It acts on the brain’s temperature control centre and tells it to return temperature to normal.
Shaving only removes the hair that’s exposed. It does not remove the hair root. Your leg hair will grow back after shaving
When it does grow back, the tip of the hair will be flat. That’s what causes the prickling. Plucked hairs grow back more naturally feel.
There is an actual medical condition, Celiac or Coeliac Disease, which is very serious, although fairly rare - only about 1% of people have it. People with that condition really cannot eat gluten because they have a strong immune reaction to it.
Gluten-free products are a blessing to these people, who would otherwise need to monitor their diet very carefully.
But since industry has now created all of these gluten-free products, why not make an extra buck on them by selling to people who don’t really need it? So they created a fad. And that is, most probably, what you are seeing.