Flat head issue

Baby is 5 weeks old and has flat head at the back and “pointy” looking at the top of his head. I bought him clevamama pillow (dimple) and he develop flat head and it got worse. I was told yaolan can help to “reshape” and make it rounder. Please share your experience on baby sleeping in yaolan. Will head return to its original shape? (or what can I do to make it rounder) i can’t find any such information on the net. I feel really bad for my baby and felt that I am such a failed mum.