I too have ultra sensitive areas on the head of my penis with a small red slightly swollen spot and red area under the rim which extends diagonally down towards the base for about 1cm. A dark area on the head near my urethra seems to be the most sensitive but when erect the red area which looks like a healing scar feels as if thin skin is stretched tight (which I suppose it is) and makes sex almost impossibly painful. For many years the head of my erect penis has shown several large well defined areas that seem slightly shiny, raised and redder than the surrounding skin but when I have mentioned this at check-ups I've been told it's nothing to worry about although no explanation was offered. When flaccid, the symptoms look minor but short of trying to get an erection in the surgery I can't think how to deal with that. This condition has been ongoing for almost 6 months now.
I have been in a monogamous heterosexual relationship for almost three years and the appearance of the symptoms indicate it may be to do with unprotected oral sex with my usual partner.
A doctor at an STD clinic in the UK declared it wasn't one and advised me to see a skin specialist which I am now doing, but following a course of Amoxcylin and anti fungal ointment and now antibiotic ointment things don't seem to be improving.
Other than this I am in reasonable health (and unstressed!) but the persistence of this condition and its striking similarity to that of the OP leads me to ask for your thoughts.
This discussion is related to
Extremely sensitive penis head after unprotected oral sex.