Know the feeling, and it's not a good one! After a similar experience, I began soaking ALL new fabrics over night in a robust vinegar bath then washing. The attached photo is the 'morning after' water from some black, name brand fabric. I shudder to think what would have happened if I'd not soaked.
Good luck removing the unwanted color; I'm sure Mum will love it knowing that you made it especially for her.
"Morning After' vinegar bath water
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