Thin Leaves = Overheating? (Pics!)

Check these out. 4 weeks into flowering and I'm really behind. Have enough light, but I'm just not sure what this is about. I have a fan on them now, but the temp got into the 87-90 degree range there for a little bit. Help me please?

just temps too high. let it chill for a few days. and thin leaves are a sativa characteristic. but the curling is heat damage.