Artifacts when masking in Lightroom

[KMi16]

Hey Everyone,

I'm editing product photos for a clothing brand and the lighting washed out one of the colors during an impromptu shoot. I used a masking tool and color pointer in Lightroom to enhance the pink in the design, but I'm getting a strange artifact when I boost the pink. Does anyone know why this might be happening or have an alternative solution to achieve the desired result?