Then came the Fourth Week. The chart said: Move to 0.5 mg. 37 clicks.

The 0.25 mg line sat perfectly in the center of the window. She had obeyed the chart.

Then she made a new rule: Every Tuesday, she would sit at the kitchen table, count the clicks aloud, and never trust her own confidence again.

She dialed past 19, past 30, past 35. At 37, she stopped. The pen’s window showed 0.5 mg. She injected. No problem.