I Have Had A White Powder On My Penis Accompanied

I have had a white powder on my penis accompanied by itching for the last one month. I have tried amoxcylllin tabs but still does not help. Today I have applied providone iodine ointment locally. Besides this I have been keeping the area clean as much as possible. The tip is slightly red and swollen and I am diabetic. I am uncircumcised.
Please help.