What you should know before treatment: 1.Sun allergy, have light skin disease; 2.Dark skin color; 3.Keloid; 4.Taking special drugs, such as retinoic acid; 5.Chloasma; 6.People who have unrealistic expectation on the treatment effect. Reactions after treatment: 1. There may be burning sensation, which can be relieved or subside after 1-2 hours. 2.The color of the original pigmentation may deepen; the red blood is more obvious, which can be reduced in about 1 week. 3, Individuals with heavier conditions or darker skin color may experience redness and swelling, or even blistering, which usually takes 1-2 weeks to subside naturally. 4, very individual may occur after treatment skin color deepening or lightening, generally temporary, most can be recovered within a few months.