Fi, as has been stated, the cause is the frenular artery is severed during the circumcision and this results in a diminished blood flow to the underside of the glans in the area of the frenulum and urinary meatus. It most often presents as a red, irritated or weepy area on the underside of the glans. Originally, it was suspected to be caused by inattentive mothers who did not change their son's diapers frequently or often enough and was suspected to be a case of amoniacial dermatitis. Now they know the cause and it is a very common complication of circumcision. Because the blood flow to the area is diminished, the area is starved for healing oxygen and the normal wear and tear occurs faster than the child's body can repair it. It seems that most outgrow the condition. I suspect that is because the area becomes so heavily scarred that there is eventually a barrier of scar tissue. The condition can go on for years. I know of one mother who is still battling it in her 8 year old son.
There is no cure and there is little she can do other than using barrier creams. It can become deadly by completely blocking the free flow of urine and causing bladder or kidney damage. The treatment is a meatotomy as Jen described. The urinary opening heals with scar tissue until it becomes completely blocked (or nearly so) and at that time, the urinary opening must be re-opened. This is usually done with surgical scissors. The tip of one blade is inserted into the urethra and then the two sides are brought together to cut the opening larger. In the fairly recent past, this was done with no anesthesia and is incredibly painful. Tell her to insist that she be there during the procedure and that she insist that analgesia or anesthesia be used.
Frank