2 month old has a sacral dimple, no other symptoms present. so far normal development and normal on exam. should we still be concerned?

Likely Fine: Most sacral dimples are harmless and don't require any treatment. Rarely sacral dimples are associated with a serious underlying abnormality of the spine or spinal cord. Examples include spina bifida or tethered cord syndrome. The risks of above spinal problems increase if sacral dimple is accompanied by a nearby tuft of hair, skin tag or certain types of skin discolorations.