A nitrous oxide abuser is blaming California head shops for injuries during his laughing gas highs. Doctors say Jason Starn, who must now use a walker to get around, suffered degeneration of his spinal cord because of his nitrous oxide use. The 35-year-old former Modesto school teacher filed a Sacramento Superior Court lawsuit last year against head shops in Modesto , Folsom and Foothill Farms, where he bought the drug in the form of gas chargers that go by the trade name Whip-It.