Dont worry about it. We first time growers worry about the little things because we dont know whats important. You will see in a few days the first set of leafs should appear and they will probably be fine. They are incredibly resilient, im making much more mistakes than you and they didnt die, i just got them out of a 3 week ph lock and they survived. Just make sure not to feed her any nutrients, just some rooting agent mabe, at the first two weeks or so, see the bag on ur soil, should say when to start feeding more. As it is a seedling mix, prolly 2 weeks till you start giving other nuts. Keep ur eye on the water ph and runoff water ph, this tells you hows ur soil ph. And you should be fine. Its not that little spot that is gonna influence the final product. Good luck and happy grow!😘