well i'd say its nute burn just looking at it, thats what happend to mine, so i just used water for like 3 weeks, and then the rest of the leaves were fine.... just cut the nuteburned leave(s) off Later on when its bigger, ((thats what i did)) 2 of my leaves got burned, so i cut it off... and it makes no differance.... otherwise just leave it... and pray no more leaves get burned... anyways good luck