don't give (something) another thought

Do not concern yourself with or worry about something any further. A: "I'm so sorry for breaking that vase!" B: "Oh, don't worry, it was just a cheap old thing. Don't give it another thought!" Don't give her comments another thought—she's just trying to hurt your feelings because she's jealous, that's all. Don't give it another thought—I really wasn't bothered by your questions at all. I'm glad you're so engaged with the material!