My sister just called me saying the doctor thinks her son has scabies, not positive though. My daughter stayed with her…

My sister just called me saying the doctor thinks her son has scabies, not positive though. My daughter stayed with her for an hour yesterday. Im so nervous we're going to get them. Is there anything I can do to prevent us from getting it now or prevent it from turning into bites? I'll attach photo of his leg. He plays outside alot and they have fleas in there yard so were hoping thats what it is and not scabies.