when your lights go off the plants will naturally droop.
The curling on the edges due to dehyrdration or heat. If it is just the leaves closest to the lamp you need to raise your light a few inches. If you have a fan blowing across the tops of your plants you can place the lamp much closer to your leaves.
Or use a vented hood to get the same results.
Blowing air across your plants does have a wind burn effect. But as long as the leaf is a good green color it should be ok.
I keep my light as close as I can.....and I get a few leaves curling on the edge like yours. As long as the leaf doesnt start turning brown it will probably be ok.
Good luck