PORTLAND, Maine — You don’t back out of a bet with a biker club, but you can improve on it.

In January, Stephen Betters felt so strongly the New England Patriots would beat the Denver Broncos, he promised members of the Combat Vets Motorcycle Association in Bangor that he would dye his hair and beard pink if they lost.

The rest is history.

Or is it?

Shortly after the 26-16 defeat on Jan. 19, Betters decided that if he was going to dye his hair pink, it ought to have a silver lining.

“I thought, ‘How can I turn this into a positive?’” Betters recalled. “‘How can I turn this lemon into lemonade?’”

With the help of a friend, Betters created a Facebook page called Lemonade for Kids. The page, launched Feb. 11, featured a single photo of the newly coiffed Betters holding a placard with a handwritten challenge: If his page received 500 likes by the end of February, he would donate $500 to the Barbara Bush Children’s Hospital. If he received 1,000 likes, he’d double the amount.

The goal was met within 24 hours.

The next day, he had more than 1,300 likes. A week later, on Wednesday, Feb. 19, he was featured on a local TV news show and had 2,200 likes. A day later, his story was aired in Germany, the Netherlands and New Zealand, and his pool of followers grew to 3,600. On Thursday, he was interviewed by CNN. As of Friday morning, the page had more than 4,000 followers.

Within two hours of posting his photo, Betters was recognized by a complete stranger in a Portland pharmacy. He said the stranger gave him a “big bear hug.”

“The darn thing has exploded on me,” the 58-year-old Portland native said. “It’s incredible.”

Betters, who will donate $1,000 out of his own pocket, said the page has inspired others. In some cases, people share stories of their children and the care they received at the hospital. Others offer to contribute money of their own. In one case, a photographer in Biddeford offered to contribute another $500 to the cause if he received 500 likes on his Facebook page for Visions of Maine.

There’s no personal story behind Betters’ decision to donate to the Barbara Bush Children’s Hospital. He has two adult children and five grandchildren — with two more on the way — but none of them have had any experiences at the children’s hospital.

“All I wanted was for people to take a moment of their time to stop thinking about world problems, political issues, even their own struggles, and just for one second before they hit that ‘like’ button to think about children and their situation,” he said Thursday.

Betters graduated from Deering High School in 1973, had a 20-year career in the U.S. Army, and now works the overnight shift for the U.S. Postal Service in Scarborough. An avid motorcyclist, he is also a member of the Gray chapter of the Combat Vets Motorcycle Association.

The pink dye, which is called “Hot 4 Pink,” is nonpermanent and washes out easily in the shower. He doesn’t wear it every day, he said. It takes about 30 minutes to apply between rubbing it into his hair, blow drying it and setting it with hairspray.

His natural hair color is gray.

“I like to call it light, light, light blond,” Betters quipped.

He said his new look has been embraced by friends and most strangers. On Thursday, while standing outside his split-level ranch-style home in the Rosemont neighborhood, passersby often slowed to take a good look at his fuchsia mane, which contrasted vividly against his black leather jacket and a fresh coating of snow.

The next step for Lemonade for Kids is uncertain, Betters said, but he and a friend are working on a website. He has also been asked to dye his hair purple in June to raise awareness for epilepsy, and to go green in March for St. Patrick’s Day.

Despite the sudden wash of attention, Betters said he’s taking it all in stride.

“I’m just a guy who’s doing the best he can,” he said. “I never intended for it to get this big.”