Move your lights up. Mine did the same, when they where 2 and 3 weeks old. The leaf tips would start pointing up, so I moved lights T-5s 4' 4 bulb up from 18" to 24" and that made the problem go away in a day.
My temps where running close to 80 and my humidity was 59-60% I raised lights and that help bring down temps and lower humidty. Over night the temp went to 75 and humidity was 50% My Kush and Northern lights plus skunk all went POW, leaves where looking beautiful they where just out and lifted slightly up like praising the light.my temps are at 80 and the humidity is at 35-40%