Never letting them see you sweat has taken a scary new turn in Hollywood. To guarantee a well-timed dry performance, celebs are visiting dermatologists for injections of Botox, a drug derived from a biologic toxin that temporarily immobilizes the glands responsible for releasing sweat. Botox has been ironing out wrinkles for years, but using the drug to stop sweating is gaining popularity. The procedure, which costs between $500 and $1,500, results in six sweat-free months, and can be repeated indefinitely. ”Celebrities do it when they’re going to be wearing couture,” explains Manhattan-based Dr. Patricia Wexler. ”They don’t want to get overheated and ruin their gowns.” Wexler, who has a large star clientele, does the procedure nearly every day, and much more frequently in the weeks before a big event like the Oscars. And it’s not just for the underarms. ”We do palms — people can’t shake hands when their hands are sweating,” Wexler says. ”Also the neck and the forehead, which can bead under hot lights.” Speaking of which, why don’t the sweatless ones swoon from the heat? ”The sweat glands under the arms don’t perform any life-sustaining function,” claims Manhattan’s Dr. David Orentreich, who also performs the procedure. ”They’re primarily scent-marking devices, and are minimally involved in regulating body temperature.” Leave it to Hollywood to find a new way to fool Mother Nature.