The totals will go back and forth, but it's all about turnout proportionally in in- vs out- regions versus original projections. Glasgow was expected to be massively pro-remain but did Glasgow turn out in higher/lower numbers than anticipated? and did Glasgow go more or less pro-remain than anticipated? I would be very very worried if I were a British citizen in the remain camp right now.

Depends on how Glasgow was predicted to vote in their model. If it matches their prediction then the impact would be limited.