The slightly pink scar that traces a path from her left temple to the top of her nose can't begin to indicate the severity of the head injury she sustained on December 19, which is when she got into a car wreck with her boyfriend.
She also suffered an internal decapitation called an atlanto-occipital dislocation, which is a rare medical condition where the skull separates from the spinal column during a severe head injury. Most people don't survive it.
On Friday, McKinney walked slowly and talked with animation. But it was Thursday when an amazing breakthrough occurred.
"I shaved my legs yesterday," McKinney said with excitement. "It was pretty awesome. They were getting pretty ugly."
She did it with her left hand, which felt dead until a few days ago. Intense physical therapy at the Baylor Institute for Rehabilitation has helped McKinney relearn control of the left side of her body. That side of her body still does not quite follow all of her commands.
One of the rehabilitation exercises requires picking up washers and placing nails in a hole with a pair of tweezers. The task requires dexterity, control and arm strength.
She also works the back and leg muscles, as she sits in a certain position while accomplishing the task. There is so much more to treating traumatic brain injury patients than physical drills, "including speech therapy, occupationally therapy, physical therapy, neurophysiology, recreational therapy, which tries to incorporate what patients did before, what their passions were before," explained Dr. Randi Dubeil, medical director of Baylor's Traumatic Brain Injury Program.
"This level of care we like to provide three hours of rehabilitation a day," he said. "It doesn't sound like a lot, but you would be amazed. Fatigue is an incredible part of recovering from a traumatic brain injury."
Dubeil said initially, moving from a lying to a sitting position or sitting to standing can exhaust a patient for the entire day.
Intense inpatient therapy typically lasts four to eight weeks after an acute injury. Therapy typically continues for months after that, if not years.
McKinney, like many brain injury patients, also has some amnesia. She said the fog is lifting with cognitive therapy.
"[For] the majority of patients, the quickest recovery happens in the first six months," Dubeil said. "But, that doesn't mean the end of their recovery. Recovery can happen as long as two years, and even beyond that."
Research also shows the quicker the recovery, the more complete the person will recover. Experts said the fact that Gabrielle Giffords is showing daily progress this early is a very good sign.
A few weeks into treatment, McKinney is becoming more like herself again.
"I can't believe I was supposed to die," she said. "I've had like a lot of people that have cried and stuff. But, I'm making it; I'm doing good. I'm getting better, and one day I'll be back to me and doing good again."
McKinney had not heard of Giffords, but when it comes to recovery, the teen had three words of advice for her and her family: "Don't quit believing."