Red Scales/blotched Penis

Hi

I have been having unprotected sex with my girlfriend now for quite some time. I have had red marks appear on the head of my penis now and am worried that I may have an STD or some other skin infection.

Heres the symptoms

3 red marks on the head
completely painless and non-itchy
sometimes they feel smooth sometimes scaley
one looks like it is made up of small clusters
biggest mark is about 50mm across
have lasted for 2 months
no other problems anywhere else on body
girlfriend has no symptoms at all

I have checked the symptoms of herpes and they appear to be painful blisters which burst which fortunately is not hapening to me. I have had a similiar problem in the past near my frenelum but it turned out to be a skin problem and not an STD. I was prescribed Canesten HC Cream which I have tried using with my current problem but its not reducing the redness.

Im hoping its something harmless like a change of washing powder having an effect on my skin. In addition im working abroad in a non english speaking country so seeing a doctor isnt as easy as it sounds.

Any advice would be appreciated. Thank You !