In extreme cases blistering may occur, which heals in a few days. Cooling, healing gel or ice-packs should be applied frequently to alleviate discomfort. Treat this situation as you would for sun burn.
Blanching or hyper-pigmentation will only occur if strict guidelines regarding settings for the different skin types and colours have not been adhered to; OR if the client has not disclosed all contra-indications, medications. or the full extent of their sun or UV exposure during the month prior to treatment. Usually blanching or hyper-pigmented scars will heal and fade over weeks or months, but in extreme cases, especially on darker skins, they could be permanent.