I had a small blister on my buttock(end part of spinalcord) and the surgeon removed that part. but after 2 years it happened again suggest me.. ?

Big difference: Pilonidal cysts which occur where the two buttocks join at the end of the tailbone (coccyx), a common problem. These involve only skin & subcutaneous tissue; frequently recur after surgery. Cysts can also occur at the lower end of spinal canal, called meningoceles. These are deep structures & potentially quite serious. But the 2 conditions are quite different. Ask your doctor which you have.