rash around penis???

I have a rash around my penis and it has not gone away. It itches but when i scratch it seems to get bigger. Dont know what it is? I dont think its std's i just only had sex 3 times w/ the same girl. but thats been over a year. Does anyone one what i can use to make the rash go away i have use cortaid but it did not work. So if anybody have a solution for my problem plz leave me a response thank you..