I do keep an eye on moles - and the one on the back of my neck, I get DP to keep an eye on.
Sunblock was very well known by the 80s - my mother didn't believe in it (she had olive skin whilst I was the irritating pale skinned, freckled kid who keeled over in the heat as soon as it got over about 16 degrees and always insisted that if she could tan beautifully with just cooking oil, I definitely didn't need 'overpriced muck' or a hat for days out) - and neither did one of my exes, who grew up going on holidays to the hottest places possible, armed with just Ambre Solaire oil to make sure everybody knew they'd been to Morocco.
He claimed that getting as much sunburn as possible, a minimum of six hours out, on the first day of sunshine meant that it would teach your skin not to burn and you'd tan for the rest of the week. I do remember him having a very dodgy looking, unevenly shaped mole on his back, but by the time I noticed it, he'd turned out to be a dick in more ways than that (the 'people only get ill because they want to be, disability is always due to lack of moral fibre' type), so I assume that somebody else has drawn it to his attention by now.
I think I had 3 severe sunburns in all, as in blisters all over, headaches, shivering, sheets of crispy skin breaking off in one due to the lack of sunblock, but I've never been on a beach holiday, so I've not done a fortnight every year for 40-odd years to increase the likelihood as much as some.
As things go, I keep an eye on them, but I don't actually worry about it, as if they change, I'd be straight down the GP wanting a referral. I can't change the past, I just have to be aware of any changes.