Hey there, those spots could be one of two things. Either pests, and just to make sure , check underneath the leafs : if you see microscopic black spots under the leafs, i'm sorry to say you might have spidermites . If that's the case try BT, that's what works for me, and it's bio. What i think is more likely is that you're seeing the first signs of calcium deficiency : you can tell by the scaterred rust spots on the leafs. Try adding more calmag to your feed or making a foliar spray with 3ml/L twice to three times a week just before lights on. The problem should stop spreading and the plant should recover in 7 to ten days. Hope this helps ! 🚀