Fresh urine worked much better than iodine, at least for me.
Simply soak the affected region with fresh urine for 10-20 mins, 2-3 times a day. Use a spray bottle/bandage or soak in a small container if necessary.
Very efficient at pain relief (1st day) & closing of sores. Crusting appears on 2nd or 3rd day. Sore is totally healed in 4-6 days with minimal pain throughout.