Hard to tell with the lighting, but thrips are bad! As stated below—- spray plants in veg with neem (right before lights out), get some sticky yellow soil bug traps, and maybe some diatomaceous earth powder for the soil. They can get out of control very quickly!
The white dots are from the thrips. You should get some Neem oil, spray it on the soil and also lightly as a foliar spray.
The yellowing and browning of the leaves are probably a separate issue, it looks like potassium deficiency.