tips of leaves curling up?

My plant is just finishing its third week of veg. Yesterday I started 12-12. The tips of some of the leaves near the top are curling upwards have been for about a week. I suspect its because my temp. is kind of high. I try to ventilate the best I can but despite the effort some days my grow room reaches 90 plus. Now that the lights will be on 12-12 it should keep the temp lower. Does anyone else think it could be my grow room is too hot. Ph is good and I havent over or underwatered the plant. Any opinions will be appreciated Thanks

yup sounds like heat burn my friend pics would prove but def try and get those temps down.

90+ will kill them.

Thanks for the info guys