<s>[INST] Hi this is AAAAA from bangalore. My friend got some problem . He is 38yrs old. 2 days back he got sudden rashes on his left part of face and it is burning. 2nd day it bacome red coluor. and 3 rd day ie., today it become complete black colour. only on his left part of face and slightly passed to left side of neck . Still it is burning. and it is severe in day time when exposed to sun light and even in house. This is first experience to him. what could be wrong and why it is so. [/INST] Hi, Thanks for writing here. It seems your friend has got severe sun allergy. Ask him to stay indoors as far as possible. Do not apply any soap over affected area. Ask him to apply ice or cotton cloth soaked in water. Start applying a steroid cream like mometasone over affected area two to three times daily. You can also give him anti-allergic tablets like cetirizine at night. In case there is no improvement it will be better to consult a dermatologist. Hope this will solve your query. Take care. </s>