Suffering from both heat/light stress and N toxicity. Raise your light a few inches and see how she responds. Lowering the intensity may help too. Being so young, they like spring lighting conditions and environment. So 19-22'C Temperatures and 60% RH. I would just water her with clean pH 6.2 water for the next couple of weeks and allow her to recover from being overloaded. I hope this helps, good luck with your grow