Hi!
Unfortunately the creaming is not effective with ringworm.
Can you get hold of a human anti-dandruff shampoo from your pharmacy and give your piggy a full body bath every 3 days?
This will help to stop any new infection herds before they can develop, deal with the acute herds and wash off the thousands of long-lived ringworm spores that can each cause a new infection outbreak on the body.
Creaming can unfortunately only deal with a small part of the affected area but cannot reach the whole patch and cannot prevent further infections. The fungal hair shampoo (like nizoral) is rather rough on the guinea pig skin but seeing that you are in a country where getting suitable products is much more difficult, this is likely the most effective treatment accessible by you if your vet is not willing to try a systemic oral anti-fungal cat medication. Both methods do work much better than creaming. You should be able to get over the acute ringworm after 3-7 applications of the bathing, depending on the severity. The pictures at the end of the guide will help you to work out when you have stopped the ringworm outbreak.
Even if you continue just with the creaming regime, you still need to give anti-fungal baths in order to remove the spores and prevent them from infecting other part of the body and causing a new outbreak 10-14 days later...
The other thing you REALLY need to do is a deep clean with a vet grade antifungal (and not just antibacterial) disinfectant in order to get on top ringworm. Please be aware that ringworm (tinea) is highly contagious and is the biggest issue that passes between species, including other pets and humans.
Please take the time to carefully read this guide here, bookmark it and follow it diligently. It is VERY detailed and practical; it has also help a goodly number of forum members to get rid of ringworm once and for all. I have also included some product names that should be comparatively easily available worldwide.
Ringworm: Hygiene And Pictures