One of my old Doctors had been a Dermatologist in another country before me migrated and became a family doc. He was an awesome resource to talk to about skin issues. I remember having a discussion with him about melanoma once. He said that in his career, the only melanoma he'd seen which was advanced and serious were the ones where people had ignored/not spotted really obvious changes until it was too late. In his words "once it had become a black, bleeding lump, only then would they would go to the Doctor". I guess as someone with HA I cannot even imagine this, but I know there are people out there who either don't know, or don't even consider their skin health until something is obviously really wrong.
I think a little vigilance goes a long way with your skin. I have tried to get away from self-checking as much as possible as it's a big HA-trigger for me, but I do keep my yearly physical and get my Doc to check everything out for me. In fact I'm going in this week for him to look at a pre-existing mole on my back which has started to look darker. I plan to ask for a referral to a Derm, and will arrange for annual appointments with them too.
But I really think you're right - skin just changes over time. The vast, vast majority of moles, even new and/or weird-looking ones are benign and no cause for alarm. Of the few which actually are melanoma, the vast majority (I think over 90%) are caught early and cured by surgical excision alone. It's such a tiny percentage which become really serious.
Sounds like you're on top of your skin issues, so regardless of what this dot is (and I'm sure it's benign), it's going to be dealt with in plenty of time by a specialist! Good luck at your appointment!