The redness and slight swelling of the face on the third day of the medicated water spot removal may be a normal phenomenon during the recovery period, or it may be an abnormal situation such as infection, allergy, etc. At present, the treatment of medicated water spot removal is usually not recommended to remove the spots in the clinic. 1. Normal phenomenon: The main purpose of potion to remove spots is to use corrosive solution with suitable concentration and apply it on the skin spots, so as to corrode the spots locally, cause local chemical burns, destroy the local skin tissues of spots, and achieve the effect of removing spots. After treatment, there is local healing process of crusting and descaling, resulting in slight redness and swelling of local skin after spot removal, which usually can subside by itself. 2. Infection: If the aseptic operation is not strict or the local clean and dry, scientific care is not paid attention to after the removal of spots, it is easy to cause infection, resulting in local redness, swelling, heat and pain symptoms. 3. Allergic reaction: when removing spots with medicated water, if you are allergic to the medicated water used, it is easy to have an allergic reaction after removing spots, which may lead to the symptoms of redness and slight swelling on the face. It is suggested that patients should combine their own situation and go to regular hospitals for consultation in time if necessary, and follow the advice of specialists to deal with the problem reasonably so as not to delay the treatment.