A little off topic, but your laundry should never be in a condition to allow mold growth. Stuff should be allowed to dry out if it got wet (if you don’t intend to wash it soon) and washed laundry should be promptly dried. If you are doing that and it still happened, you might have a mold problem in your home. The shirt might not be saveable, but this might be the lesson to avoid more expensive mistakes in the future.