It could be fungal infection. Whatever ur doing is correct but still other things need to do.. if u r over weight try to reduce it, if u r fond of sweets, oily fatty food and NV & vinegar.. please avoid till to get cure. Keep hygiene and dry the private part.. antifungal and antibacterial ointments will be for time being or may hardly cure..
Next Steps
for the permanent cure consult a Homeopath for constitutionally medicines for such infection.. definitely it will help you to get free from this problem.
Health Tips
take enough fluids, get good sleep, stressful life? need some relaxation, go for urine ROUTINE test.