Hello,
Since you have mentioned that you have 3-4 such spots, so the other possibility is of Fordyce spots. They are
small, painless, pale spots or
bumps 1 to 3 mm in diameter that may appear
on the
shaft of the penis. The spots are a form of ectopic sebaceous gland, and are not known to be associated with any disease or illness and are of cosmetic concern only. Both penile melanosis or Fordyce spots are not symptomatic of penile malignancy and are harmless.
I sincerely hope it helps.