I wouldn't be surprised if Scotland eventually leaves UK and joins the EU. Part of the reason they voted to stay in the UK was so that they could remain in the EU, and then brexit happened
They would then have a hard border with England, and would have to untangle their economy from the UK to some extent, which would be extremely disruptive. There will also be complex issues around who gets which citizenship, who would need work visas, a change of currency, etc.
It was known that there was likely to be a Brexit referendum at the time of the Scottish referendum: Cameron had promised one if the Conservatives won the 2015 election.
That can’t happen though because they’d be without a currency in the interim period and it’s also baked in to the EU’s treaties to make this difficult else places like Catalonia and the Basque Country would break away and join the EU, so there are barriers in place to make this less than quick or easy.