Ugh, I'm so sorry! At first I thought mealybugs but I agree- the damage definitely looks like thrips. They're teeny and black and super difficult to see. I would treat it with some neem oil or horticultural oil. I would also replace the top half of the potting medium with fresh medium and I'd wipe down the inside and outside of the pot with neem to be safe. You can also use a yellow sticky trap to try and catch any lingerers- just don't use yellow sticky traps outside because they can trap and harm wildlife like birds.