I had these on my legs and went to a dermatoligist for ultra treatments. They did not work. I was told these were from nerves. I went home and scratch them open and poured original Listerine on my legs and the itching went away.
It means that you have some kind of infection which maybe due to food allergy or insect bites. Dont scratch that place. Instead clean it with some antiseptic solution and consult your doctor.