Hello, most umbilical hernias do resolve unaided. However you son may need treatment, which is a simple surgery if the hernia is increasing in size (tummy getting bigger), if he's vomiting, if the tummy colour is getting darker, if be pain is persistent, if the hernia still persist over 4 years of age so be on the look out. Hopefully it would resolve on it own. Cheers.
Medical Doctor at Ekiti Teaching Hospital