ok, do you see it in other places?
try bending a branch away from the center to check inside it maybe worse, you probably have white powdery mildew. you won’t be able to get rid of it, but might be able to control it enough to get something good..
maybe start a post of what to do with white powdery mildew, there’s lots of ways but i don’t know what would work best..
i find in southern ontario you need to grow sativa strong strains because they love heat and humidity, wear as when indica’s start to flower they need a less humid environment and cooler too kinda..
you’ll see most people with it outdoors around here with indicas, i know of lots so far, also lots of sativa strong with nothing in same garden.