Mild sunburn usually lasts 3-5 days. Moderate or severe sunburn usually lasts several days longer. Generally depending on your skin complexion and severity of the burn the pain will last 2-4 days, less if the burn is minor, more if the burn is severe(in which case seeing a doctor is not a bad idea). Also peeling which generally occurs wi... http://wiki.answers.com/Q/How_long_does_a_sunburn_last. All sunburns are different according to how bad you got burnt how tan you already were etc etc... but normally the pain should ease in three or four days by a week your gonna feel a lot better, oh and make sure to keep moisturized when you ...