Any ideas about getting rid of black tongue quicker?

My Mom has a black tongue and I have read that it's a yeast overgrowth and I also read that Humaworm will help that. We ordered it but until it comes, does anyone have any quick remedies to get rid of it besides just brushing the tongue 3 times a day? She has a wedding to go to and is embarrassed.

Also, she has seborrheic dermatitis on her face which I read is also an overgrowth of yeast. We ordered the Humaworm cream but any suggestions that would help in the meantime would also be appreciated. Thanks in advance.