As Dr. Erfani stated, this is most likely a mucocele, a single clogged tiny salivary gland. However, once surgically removed the SAME gland can never reclog, since it is gone. Therefore, you have another one, even if it seems the exact same place. You have thousands of tiny glands in your lip. You may be best treated by another removal. You could get another one later, but that would be unusual. Good luck.