A clinical examination is necessary for confirming the diagnosis. Small dome-shaped bumps around the crown of the head could probably be due to pearly penile papules. They are not infectious and may be seen in about 10-20% of all men. Small red or purple spots with a thick, warty surface are angiokertomas. They require no treatment. A boil or folliculitis is another possibility. It could also be due to friction or heat rash. The presence of associated symptoms will help in narrowing down at a suitable diagnosis. See a dermatologist.
Best luck and take care!