My Husband Burned His Skin With A Diluted Mix Of

my husband burned his skin with a diluted mix of water and oven cleaner...he did not realize that what it was because it was in an unmarked bottle at his cooking club (duh...) he had the bottle hooked onto his belt and the residue leaked onto his jeans and onto his skin creating burns...I wash with water and put a compress of plain water on it which cooled the pain...I covered the wound loosely with gauze and off he went...anything else I should do?
Thanks so much