(INSIDE EDITION)- Revenge is sweet, but this apology is even sweeter.
Rachel Gelmis, 20, told InsideEdition.com that when she was the 11th grade, her mom asked her private high school to perform an optional drug test on her.
"I had been acting weird, and she assumed I was just smoking pot or something," Gelmis said.
But, the results were shocking.
Gelmis said the school had contacted her mom before the pair got a chance to talk, and announced in a the 16-year-old had tested positive for every drug on the panel, including marijuana, cocaine, heroin and meth.
"She wasn't mad, she was scared and disappointed," Gelmis recalled. "She went into panic mode and had something of an emotional breakdown on the way home. She kept talking about rehab."
Gelmis remembered being sent to her room as her mom and dad continued discussing options until a few hours later, her school reached out again.
They realized they had misread the results, and the teen was actually completely clean.
"[My mom] felt pretty awful, because she hadn't trusted me," she said, "but what parent is going to trust their 16-year-old over what they thought was a well-administered drug test?"
So, to milk the accident for all it was worth, Gelmis suggested her mom make it up to her by baking her a cake.
As Facebook's new Timehop reminded her, the cake her mom presented her four years ago read: "Sorry we thought you did meth ... and coke and pot and heroin."
That time my mom genuinely believed I was doing every drug at once bc my idiot school misread my drug test
"Our relationship is very goofy, so asking for a silly cake wasn't entirely out of the ordinary," Gelmis said. "I knew it would be something that would cheer us both up and it would alleviate some of her guilt."
Even though the awkward encounter has been long forgiven, the current University of Alabama student said she still doesn't let her mom live it down.
"I still give her a hard time about it to this day," she joked.