Similac total comfort formula

Any mummies giving their baby similac total comfort formula? My baby has rashes on his face for 2 weeks + now and we decided to change from friso to similac. However we notice a big change in his diaper change. In past 24hrs he didnt poop at all. Is this normal? Does anyone encounter same issue? As for Friso he poop at least 5 times in 24hrs…. Please advise..