Hi Nat.
They would be there when you've finished, it's just they're easier to see when they've fully dried.
Without a doubt it's the edges of your squeegee.
Have a look at them, there may be a slightbreak or cut in it.
If you've plenty of overhang, then just cut the edge back a bit, and make a nice square edge.
If not, it's time for a new rubber, or at least turn it over.
Have a look at all different angles when you've finished, and buff it there and then if you see anything.
One big tip...
When you're not using your squeegee always keep it submerged in water.
It will dry out very quick, then it won't work properly at all. I didn't work for 3 weeks and my squeegee was fine, but I've left one dry for a weekend and it's been ruined.
Rog.
ps: Well done everyone for the help you've given the new guy. :
It wasn't exactly a hard question for anyone to answer.
But then it shows that all anyone cares about is wfp... :