I Have What Looks Like A Rash That Itches On

I have what looks like a rash that itches on the shaft of my penis and has recently moved to parts of the foreskin. I have had it for over a week. 5 days ago i bought an over the counter anti fungle cream. The redness and irritation go away over night but once i leave the shower after washing there, it becomes itchy and somewhat inflamed. If it isna fungus, shouldnt it be gone by now?