Mix 250 ml of water at room temperature and a spoonful of sodium thiosulfate until it dissolves completely.
Pour the solution directly onto the bleach stain and leave it to act for a few minutes, then wash the garment with cold water. Do not rub.
Second trick
Mix two equal parts of alcohol and white vinegar. Dampen a cloth in the solution and apply it to the stain, giving small touches but without rubbing.
Wash the item with cold water and, if necessary, repeat the process until the stain is completely gone.
As you can see, it is possible to recover a garment that has bleach stains, you just need to apply one of the two tricks described above.