Hi, what that one need? All the same soil.

I don't see any powdery mildew. Looks to me like a combination of too much nitrogen and a deficiency of trace minerals, probably iron or zinc (as it is the new growth showing symptoms). A dose or three of soluble trace mineral mix, available from any decent garden center, should help things. Also, try to avoid wetting the leaves, you can see where previously this has led to burned patches on the leaves.

What to do? Not sure there is much to do, prevention is the best remedy, understand what it is, understand what caused it, then remove the possibility of it happening again. Treating it needs to come with a change in environment, or you will quickly face the same problem again. See a little nute burn on margins too, leaves curling up, so it could be many little things. The only time I have seen mangled shit like that, and it not being an animal/insect, is a very strong denaturing of the enzymes that hold the plant together, if exposed to very high temps for too long. When the teeny tiny little leaves are small, the heat kinda "melts" the enzymes for lack of a better description. Once temperatures return to normal, the plant tries to resolidify the mini leaf's structure, but often, once it grows out days/weeks later, it looks very similar to having been chewed on, just chaos. The top of your canopy should not go over 86F, very easy to lose cooling or fans for whatever reason, so make sure everything is flowing. Might have salt buildup, gonna need to know more than a picture. Good luck

Looks like your cat chewed on it Also possibly powdery mildew or something starting on the leaves. I'm not sure it's a pest. But a fungicide should take care of it just fine

Bacteria needs 3 things, food, moistue and temps. As a plant spits water out all night if there is no air to take away the tiny vapor particles around a leaf it creates a 100% rh zone around the leaf and until air comes and "resets" the leaf, all gas exchange ceases. The plant exuding a liquid containing sugars onto its leaves, particularly at night or in the early morning, is called guttation. We got food, moisture and temps. If temps go above 77F bacterial multiplies at 20x the rate. Game Over. Please add new seeds to continue. The end.

To me, it looks like powdery mildew. As long as you’re not in the flowering stage yet, try to remove it. If it’s too much, I would throw the cannabis plant in the trash and completely disinfect the tent.