I guess keeping a phone in a pocket is a bad idea! Never done that, so I wouldn’t know.
I’ve never sunburned badly enough to blister. But there was a period of my much earlier life where I dwelled on islands with remote beaches where I camped out and swam nekkid and was tan without any bathing suit lines! Now that I’m a Floridian, I never quite revert to my au naturel pasty white (on my uncovered areas, that is LOL). So I never really even burn enough to peel anymore. I’m usually fairly tan by late spring just from my routine outdoor chores. That’s part of the reason I wanted all of those moles gone. That and the fact that they were an ugly nuisance. ;)
It’s the burns when you are a child that are the concern. Just like the folks who started smoking while they were children (teenagers) are more susceptible to lung cancer.