It sounds like a fungal infection (not uncommon in the nappy region and I'm surprised the GP's haven't suggested it!). Fungal infections appear 'spotty' and are immune to basic barrier creams - sound familiar?! You need an anti-fungal for it. I remember using Daktozin on my DS and your pharmacist will be able to advise you which is the best one these days. You also need to check with the pharmacist whether it's ok to use the anti-fungal on an open and pussy sore (I assume it is open and weeping?). How big is the pussy spot? A pinhead, a five cent piece...? If your DD develops a temperature or becomes lethargic and unwell you need to insist on seeing a doctor immediately or head for your nearest hospital as the infection may have spread to her blood stream. Are you sure the doctor's in town won't see you if you explain the situation? Most will make time for children. If not, speak to a pharmacist and ask about an anti-fungal.

As for miracle cure... I have heard numerous times that honey is a miracle cure for infection (applied, not eaten!) but I don't know enough about it to recommend it!