Did you Google “Seborrheic Keratoses”? That would explain it. Big Brother is wathcing you. Get a Linux phone and use DuckDuckGo.
“I had not done any searches online, for either skin cancer in general or for this specific lesion, not now or ever.”
I have had DuckDuckGo searches picked up into adware recently. I was curious and tested search it for some odd things.