Schwartz negated an automatic review that would've likely gone his team's way when Houston's Justin Forsett ran for an 81-yard touchdown in the third quarter to help the Texans stay close enough to extend a game they won 34-31 in overtime at Detroit.
The officials failed to see that Forsett was clearly down, letting the play go and allowing him to pull Houston within three points and make Schwartz so mad he lost his composure.
"I overreacted," Schwartz acknowledged. "And, I cost us."
The Lions (4-7) have a long weekend to think about blowing a second straight game and making a return to the playoffs improbable.
Schwartz was rewarded with a contract extension in June, entering the final season of his original deal, and insisted the team's off-field problems during the offseason didn't mean his players lacked discipline.
The Georgetown graduate, though, showed his intelligence can't always overcome his ability to keep his composure.
Forsett was clearly tackled by two Lions, but the officials didn't blow their whistle when his left knee and elbow hit the turf before he popped up and sprinted for a pivotal score.
That's when Schwartz lost it.
Schwartz threw his challenge flag and knew within seconds that he made a big mistake, telling his assistants and players on the sideline, "It's on me," repeatedly as he tapped his chest with shame.
"He explained to us what the issue was with that," Matthew Stafford said. "I didn't know that was a rule and that's a tough one to swallow."
All scores in the NFL are automatically reviewed, unless a coach challenges the play.
"The thing that was most disappointing is he was down on the field and nobody blew the whistle and the guy got up and kept on running," Schwartz said. "But that's still no excuse."
Four days earlier, the Lions lost 24-20 to Green Bay.
Detroit led the Texans and Packers in the fourth quarter and wasted opportunities to win on both sides of the ball each game.
"It's kind of the same story," defensive end Kyle Vanden Bosch said. "It's just frustrating. Back-to-back weeks, we had a chance to beat a really good team, but that's not good enough because this is a really good team. We're just not playing like it right now."
Schwartz might not have been the only one who made a poor choice in the heat of the moment.
Ndamukong Suh's left cleat connected with the groin area of Houston quarterback Matt Schaub after he threw a pass in the first quarter. The defensive tackle was on his chest after being taken down by an offensive lineman when he extended his left foot to hit Schaub below the belt.
Schaub declined to say anything about the play or "that person," and Suh didn't make himself available for interviews after the game.
Suh was ejected for stomping on the right arm of Green Bay offensive lineman Evan Dietrich-Smith on Thanksgiving last year and was suspended for two games. He also has been fined in previous seasons for roughing up quarterbacks.
The actions of Schwartz and Suh changed the conversation about a game that could've been positive for the Lions.
Detroit started strong with a touchdown on its first drive and became the only team to rush for a score against the Texans this season.
Stafford missed some throws, but threw two touchdown passes and connected on 31 of 61 attempts for 441 yards. Stafford joined Kurt Warner as the only two players in NFL history to throw for 11,000-plus yards in their first 40 games.
Calvin Johnson didn't catch every ball thrown his way, but he did have eight receptions for 140 yards -- including a 22-yard TD -- and became the fifth player in league history to have 7,000 yards receiving in 87 or fewer games.
Rookie receiver Ryan Broyles had six receptions for a season-high 126 yards. Broyles made the most of his chance to move up the depth chart in place of Titus Young, who was benched for his behavior, and Nate Burleson, who is injured.
Defensive end Cliff Avril had two sacks, giving him a team-high 7 1/2, and forced a fumble in an impressive performance.
Those accomplishments happened during a loss, though, so none of them could be celebrated because the Lions missed opportunities to extend their lead during regulation and couldn't do enough on offense or defense to beat Houston in OT.
"It's gut-check time," said Vanden Bosch, who dropped what could've been a game-winning interception in the extra period. "I feel like I know how guys are going to respond. I feel like I can see the fight in everybody's eyes. Losses like this are tough.
"We'll bounce back."
That won't be easy.
The Lions' next game is at home against Indianapolis then they travel to Green Bay and Arizona before wrapping up the regular season at Ford Field against Atlanta and Chicago.