Is this a heat problem or maybe lights?

81f aint to bad i can hit that from time to time with not many issues. Hold your hand above your plant and feel the heat for yourself, also try make sure u have a fan blowing over the top of her. The humidity could be a little higher if possible they thrive a in slighty high humidity than you have in veg. All in all she will be fine though, Dont worry, for the most part this hobby is about keeping your feeds in check and your conditions at least medium quality will produce you fine buds.