The kobold screams in pain and surprise, and runs back to the group tries frantically to wipe the acid off with whatever he's got (which, it seems, is the backpack...) while squealing "Get it off! Wipe it off me! Use anything, use your clothes, just get it off me!"
That is to say, move action to move back to where I was, standard to try to wipe off this acid. 18 on the heal check, if it matters.