Sun exposure after the use of compound kallikrein tincture helps the color to recover, not must sun exposure, compound kallikrein tincture is mainly used to treat vitiligo. However, it should be noted that if you are in the progressive stage of vitiligo, that is, if you have increased and enlarged changes in the rash in the last 3 months, it is not recommended to use compound kalizarin tincture, otherwise it may stimulate the lesions to increase. The reason why sun exposure after using compound kalizarin tincture helps the color recover quickly is because ultraviolet light helps pigment recovery, but must avoid sun exposure, generally choose before 10 am and after 3 pm ultraviolet light, irradiation 5-10 minutes can be, long time sun exposure will cause vitiligo symptoms aggravated, so long time exposure is not recommended.