question: hi i have a 4 month old son who has a welt like bump on his spine, on closer inspection i noticed that it is hairy, i have concerns due to the fact that while i was pregnant with him during an ultrasound the noticed that i had an increased risk of nueral tube defect - in particular spinal bifida was wondering if i should be concerned about this lump  it is about 4cm long and 2cm wide not raised too much??