Dupuis was cross-checked in front of the net by Stars defenceman Alex Goligoski and hit in the neck or upper-back area by Kris Letang's shot from the point while he was down.
Dupuis remained on his knees in discomfort and threw off his gloves, shaking his hands before play was stopped with 6:58 remaining in the period.
"He had some numbness in his arm and it was coming back, so that's a real positive sign, but I haven't heard anything more," Penguins coach Mike Johnston said.
Dupuis was tended to while on his back for several minutes and gave a 'thumbs-up' to the crowd while leaving the ice.
"You never want to see that happen," Stars coach Lindy Ruff said. "There was a lot of concern on both benches. We've been around some tough situations and that one scared us as much as it scared the Penguins."
Dallas scored two goals in the final 2:57, the game-winner from Tyler Seguin to carry the Stars to their second straight win.
"As difficult as it is, you have to go out and play," Penguins captain Sidney Crosby said. "I don't think we let down necessarily because of that. They picked it up."
Dupuis tore the anterior cruciate ligament in his right knee last December, costing him the final 43 games of the regular season. He had four points in the Penguins' opener last Thursday.