It's hot in summer, and when I wear glasses, my nose suddenly has small white spots.

Because of the surface effect of UVB, it only appears in the epidermis of skin. Moreover, after intense sunlight irradiation, keratinocytes in the skin epidermis will die quickly, and release media to cause dermal blood vessels to dilate, thus causing tissue edema. Subsequently, under strong sunlight, melanocytes accelerate the synthesis of melanin, thus blackening the sunburned skin. Therefore, after 4-6 hours of intense sunlight irradiation, erythema with obvious boundary appears on the irradiated skin, and edema may appear in severe cases, reaching the peak at 12-24 hours. Accompanied by local burning or tingling, some may have local itching. More serious cases may cause systemic symptoms such as fever, headache, nausea and vomiting.