Hi,
Eczema usually appears as diffuse red plaques with a poorly defined edge and finely scaled surface. It frequently causes quite severe irritation. It can be caused by infection or local reaction to skin injury from chemicals or radiation. If other symptoms ar epresent and if it persists, have this checked by your doctor for proper evaluation. There are a number of effective treatments available for eczema, such as steroid creams.
Take care and regards.
I've actually got something really similar. There is no puss or white in the middle, only flesh colored. The ring isn't so much white unless the skin is dry, which leads me to believe it may be eczema.
It's not sore, doesn't hurt when I urinate or after sex, nothing. I thought at first it was a callous from receiving manual sex from my girlfriend, but I'm unsure. It hasn't moved/spread/changed in appearance since I had first noticed it about three weeks ago.
I have the same white edged crater like ring under my foreskin on top behind the penis head. I've had it for a long time like over a year or so.
I would like to know what it could be. I will eventually get it looked at. It has not changed size or spread.