I had something that faded on one of my favorite shirts. How do you get the unwanted color out?
Answers:
You could try using peroxide and a bristle brush.I'm not sure if it will work or how it will affect your fabric so you might want to do this as a last resort.It worked on getting lipstick out of jeans and a sweatshirt.
Other answers:
Carbona [color run remover] should work.
Carbona [color run remover] should work.
Some times the laundry softner will do this. If so rewash in hot wash and rinse in cold to remove.
Fabric softener sheets in the dryer will do this to some materials. Unfortunately, it's hard to get out because it gets set with the heat from the dryer. Try one of the suggested cleaners by the others...but do it on an inside seam or the inside bottom hem first to make sure it doesn't destroy the fabric or color further.
Isn't amazing how it always happens to our favorite shirt. Good luck, Sweetie.