Can an inguinal hernia just go away? or was the first vet wrong.....?

When i Purchased my puppy I was told she had an inguinal hernia. when I took her to another vet for a second opinion the vet just pointed to her lower teets and said that was the hernia. after shopping around (pricewise) about a year later we took her to a third vet that vet told us she doesn't have a hernia which brings me to ask....... could the first diagnosis incorrect? or can it just go away with time? the last vet we took her too said it just may be so tiny that it is unnoticeable. before I dump $100 for an xray thought i'd try to ask yahoo :) please only respond if you are an educated professional. my bella is too precious to take any chances. but don't want to just through money into a witch hunt. thanks!