hi dude.....
u can try something.....normally at seedling stage it is recommended if environment are a bit harsch....tu cut in half a big plastic bottle that you can pierce with 2/3 small openings
with the wet soil it can ensure a good humidity to your young plant 👍 even if i thin it is not the problem...cause in that case it should be you whole plant affected....it could just be a wind burn.....seedling a really fragile....so inside the bottle she will grow in security 👍
i sure this will help you ! 👍