most likely just clogged pores from oily skin, i get these all the time. just don't pick or squeeze at them bc then it will get a lot worse.

This could be something called Malassezia Folliculitis. It's basically an overgrowth of yeast on your forehead. Whatever you do, do not put any type of oil on it, yeast feeds off of oil and it will get worse. Google some pictures and you'll see what it looks like. If you think that is what this is, you can treat this with nizoral shampoo or head & shoulders shampoo.