What Causes Red Rashes On The Penis?

Hi Dr. I have developed red rash or very little spots on the head of my penis and there was dryness on head of or is and some skin peaked off but I had washed my penis head with little hot water for couple of days . This red rash is only in one part or area of the head of penis which is in the middle part for about quarter inches ..I'm worried about it ..
If it's any disease, it that curable ?