Hey, don't worry too much about thrips killing your cannabis plants, but they can mess them up, especially young ones. Thrips lay eggs on leaves, and when they hatch, they create small holes that make the plants vulnerable to infections. Look for silvery trails or black marks on the leaves. Spray the plants with neem oil, potassium soap, or diatomaceous earth to get rid of them. Make sure to cover all parts of the plant and spray the soil too. Try spraying in the morning or evening when they're active. If they persist, consider using an insecticide as a last resort, but be careful because it can be toxic.
and don't forget to check your growroom as well after u get rid of the thrips off your plants. But tbh I personal would do a little more research on when its too late to deal with it. 6th week pretty close tbh. but at least you can try because there is no way around I guess. I would personal go with neem oil - always worked great. But just used it way earlier. Next run u could also use it as kind of prevention before u get diseases like this.
Good luck!