When removing nevus by laser, you can hear a small crackling sound and see the dry debris of nevus tissue protein when gasifying tissue. Every gasification time, the surface debris must be wiped with normal saline, cotton swabs or gauze to avoid unnecessary thermal damage when scanning repeatedly. Gasification to black basically disappeared, and the following indications were observed by naked eyes: coarse-grained skin appendages were seen on the facial wounds, which were white granules, and most of these granular tissues were sebaceous glands; For example, dense connective tissue can be seen on the wound surface of limbs or trunk, and the tissue density gradually decreases from the dermal papillae to the deep part. When the gasification continues, the attachments in the dermis disappear, the tissue density becomes lower, and thick fiber bundles can be seen, which looks like cotton threads immersed in water. At this time, it has reached the reticular layer of dermis, and gasification should stop. At this time, if filamentous melanin or punctate melanin still extends to the deep part, it can be treated with VersaPulseQ-switched 75nm or 1
64nm laser with a spot of 2-3mm and an energy of 4-8J/cm2, and several pulses can be repeated locally.