When pores get blocked by dirt, dust or dead skin cells, an oily substance produced by the sebaceous glands gets irritated from the foreign matter. Since there is an overproduction of this, the skin erupts. When this happens, the skin pigments will turn black upon oxidation. You will notice that when you touch the blackhead infested part of your skin, that there are slight bumps on it.If the treatments or the use of the blackhead removal products is wrong, there can be adverse results. Instead of eliminating the blackheads, the small patch can get larger, the pores will get bigger, the skin will suffer from tissue damage and the problem will keep on coming back.