The lip has almost no natural sun defence
Something most people never hear: the skin on your lips has very little melanin and a much thinner barrier than the rest of your face, so it burns faster and has almost no built in UV protection. That is why sun is such a reliable trigger, and why a lip specific SPF matters more than people think. Did you know this before, or is it new to you?
How long after the first tingle do you usually have before it shows?
Winter is worse for me too, the cold wind cracks my lips and that is when they come.
Never knew lips had almost no natural sun defence. That explains so much.
Down to about two a year now, prevention genuinely works.