My matcha whisk is already moldy…

I got it on wednesday, it is a bamboo whisk. That day was also my first day having and making matcha. I was making today and see mold near the top?? I am very sad. it was quite expensive. How do you avoid mold in the whisk, and what are some other things I can use to whisk the matcha that do not mold so easily?

Edit: thank you everyone, my sister confessed to me that she did not wait for the whisk to dry and just put it in the container wet which probably caused the mold :( i’ll be more careful next time and listen to the advice!