Yeah I think they have a combination of heat stress and N deficiency. Also, they will be slow to flower because the plants are putting their energy into trying to save themselves. At best you'll be looking at a rather lean yield. If they are 6 weeks into flower, recovery will be difficult. When leaves go bad for whatever reason, its very hard to bring them back again. The hope is in the new growth, and 6 weeks in, you really dont have much time for that. Its also in the wrong time frame ( flowering) to hit them with a lot of Nitrogen.
Try to do the best you can with it and use it as a learning experience. If you continue growing, maybe try a different strain altogether.