It look like fordyce spots, nothing serious.
the discoloration is pigmentation or melanosis , penile melanoma is very rare, only 1 per cent of penile cancers.
your glans looks normal from the picture.
Go see a dermatologist.
Dave, I completely agree with what Infectologia has said. What you have on the main shaft of your penis as most likely to be Fordyce Spots, or are a completely normal part of the make-up of your penis. And again, the pigmentation differences are also completely normal. What you may have is some irritation that is making what you see more noticeable. Try not to use soap and shower gel to clean your penis with, when you wash or shower always keep the glans covered with your foreskin, to wash it expose the glans and use water only, then make sure the entire penis is fully dried with a clean dry towel.
Sending a clearer picture. See the greyish patch towards the upper part of the glans
An even clearer picture here. The grey oval discolouration close to the tip