Denver-area dermatologist Leslie Capin always knew her Chihuahua Dr. Papidies was cute. But cute enough to win $1 million? She wasn't quite sure. However, she was willing to take that chance, and entered her three-year-old pup in the All American Pet Brands' Cutest Dog Competition last fall in hopes of winning the big cash prize — with the intent of donating the reward to charity. "I know it wasn't going to be that easy to win," Capin tells PEOPLE. "By the end of the competition, there were 60,000 entries." Capin campaigned to patients, lobbied through Facebook and Twitter, and even faced allegations that she was lying about her charitable goal. "A lot of people got online and said, 'It's not true, she's going to buy a Mercedes'," she says. "But I answered them all and insisted it was true."When word came in November that Dr. Papidies had won the competition, Capin was overtaken by emotion. "I didn't grow up with a lot of money — I had to work for everything I had — and then here I am close to the age of 56, in the position to give away a million."After toasting the win with family and friends, Capin took the steps to set up a charitable trust to protect the funds. "There's an addendum that basically says should something happen to me, the trust will continue to give $33,000 a year for the next 29 years to the shelters I've chosen to help," she says. "Even if I change my mind in 10 years, I can't get that money!"As for Dr. Papidies? "I don't think he has a clue," Capin laughs. "But I wanted the two of us to make a difference in our community. To give away a million dollars... it doesn't get much better than that."