It is best not to dye your hair when your scalp is broken, because hair dye is an industrial synthetic product that contains a large amount of heavy metals and other harmful substances. If your scalp is not broken and you dye your hair under normal circumstances, the epidermal layer of the scalp forms a natural barrier that prevents hair dye from being absorbed into the bloodstream, which does not lead to serious toxic reactions. However, if the scalp is broken, the hair dye can easily enter the loose tissue under the scalp, as well as enter the blood vessels and blood, which will result in a high concentration of heavy metals in the bloodstream, affecting the hematopoietic system, and in severe cases, leading to hematopoietic disorders leading to leukemia, etc. In addition, the toxic substances in the hair dye will be absorbed into the bloodstream, which will cause a serious toxic reaction. In addition, the toxic substances in hair dyes can also cause damage to the liver and kidney functions, and in severe cases, can lead to allergic reactions, which may even be life-threatening.