Speaking publicly for the first time since her December 18 arrest on charges of dealing OxyContin, Sherry Johnston says she got hooked on the prescription drug after a hysterectomy eight years ago, which led to seven more surgeries.
"I was in pain, and I'm still in pain," she tells People.
Johnston, 42, pleaded not guilty at her arraignment in Palmer, Alaska.
"I have been trying for years to deal with the pain," the mother of Bristol Palin's baby daddy Levi Johnston says. "I still have a medical pump inside me. I would rather not comment any more but it's not everything that they're saying."
Sherry Johnston said she has been under a doctor's care and that she was prescribed OxyContin as a painkiller. Still, the hysterectomy and the subsequent complications forced her to give up her career as a hairstylist.
No comment on whether or not she deals drugs out of her house, which has been alleged after authorities had a couple of her customers wear wires.
Regardless, Sherry's spirits have been lifted by the birth of Levi and Bristol's son, Tripp Easton Mitchell Johnston, who was born on December 27.
When she saw the baby the day he was born, "I started bawling," the new grandmother says. "I think he looks just like Levi... I'm very excited."
Levi Johnston, 18, was recently forced to quit his job in an electrical apprenticeship program in Alaska's North Slope oil fields after a local newspaper columnist raised questions about whether he was eligible to participate.
Johnston says her son and Bristol Palin, also 18, plan to wed this summer.