They look like you overdosed on nutrients, or been too close to the light, just flush them with plain h20 for 2 days and keep the humidity at a consistent 55%-70% and the room temp at a range between 70-80 degrees. hopefully that helps.
Most likely some kind of stress, Possibly from a fan blowing on it, too close to light, your ph could be too high or too low, room/soil temperature could be a problem also, what kind of fertz are you feeding it? not much i hope.
I am an semi-expierenced sucsessful soil grower and am now switching over to hydroponics. I have my setup as follows:
1. 3x3 ebbnflo table
2. 400wmh
3. 30 plants, 20 sweet tooth/10 BB
they are in the first week of veg. I have them in 1.5 inch rockwool cubes surrounded by hydroton in 5inch net...