Bald spot?

My daughter get's held alot. But when we get tired we lay her down in her sleep n rocker or swing. She hate's tummy time or being on her tummy at all. So she's mostly on her back, she sleeps on her back, lays on her back. I try to turn her on her side but she goes right back on her back. Is the bald spot from her on her back all the time? it make's me feel bad because my son never had that.