Eh I feel you, this is so uncomfortable kan! Usually it's either fungal or just sweat buildup, especially in our humid weather, a few of us mummies tried antifungal cream from the pharmacy (like Canesten or Lamisil) and it helped, tapi if it's really itchy and not improving in a week or so, better check with the doctor to make sure what you're dealing with lah, because some conditions need different treatment.