Today there is genetic testing even before the baby is born. However, it is usually diagnosed at birth. Occulta is slightly different.
"Since there is no opening to the skin, spina bifida occulta can only be seen on x-ray or MRI. Certain clinical findings such as dimpling of the skin or a hairy patch at the base of the spine may trigger further investigation by a physician."
From:
Spina Bifida Occulta and Open Spina Bifida - A Patient's Guide
If there were no symptoms when your child was born, then the doctor would not have had a reason to suspect Spina Bifida.
As for what to expect:
"There is no specific treatment for occult spina bifida if the abnormality is limited to the bone. Usually these deformities are found at the last lumbar vertebrae (L5) or at the first sacral vertebrae (S1). However, deformities of the spine can lead to degenerative changes later in life that may require intervention."
From: Ibid.
Since I do not know the extent or severity of the deformity, I do not know where to direct you.