My anus is burning after having a loose stool. what does that mean? could it be something i atet?

Some possibilities: May have fissures, fistula, abscess? Sexually transmitted disease (syphilis, gc, hiv, etc.) should be considered. Hemorrhoids ; rectal prolapse can appear as a painful swelling or pain after bm. Anal trauma of any kind may cause mechanical injury. Skin eruptions need to be considered. But if fissure is confirmed, topical Nitroglycerin is traditionally used, although other agents can be compounded.