The reason of how can get effect about get new skin after got hurt on skin is because of stem cell make new skin under the damaged skin. Stem cell is undivided condition cell so can divided into specific tissue. Also possible created more many stem cell through mitosis. Stem cell is different with normal cell, stem cell can able to reproduction by one self. If incubate stem cell in medical lab, be able to increase with undivided condition 1 year or more than 1 year.