Is these heat rash? is only at the back and below the neck area. It been there for weeks. And after bath or during playing she get more and after few hours it will go off. Any cream to apply?

Zinc oxide will treat and prevent baby rash. Also, make sure to keep your baby cool and dry. If she sweats a lot, keep patting her dry, change her clothes, and make sure the room is cool and not hot. Last, are you using baby friendly detergent? Could be your baby is reacting to harsh chemicals.