I Have Redness On The Head And About The First

I have redness on the head and about the first half inch of the shaft. it itches most of the time. there is no bumps or swelling. sometimes it wont bother me for a week or so sometimes it it will bother me for up to a week at a time. I tried using athletic foot cream but it doesn't seem to work . I did use diaper rash cream once and it worked well. but I was unable to find that brand and tried others and none of them worked. also im type 2 diabetic