She's really cute. Reminds me of a sweety pie kitty my mom had.
The crust could be dried food, but really if it doesn't wash off easily you might check into URI type things...feline herpes (rhino) or calicivirus, plus some other things can cause that type of crust, too. They're not contagious to humans, and most have to run their course, with supportive care as needed. Sometimes they'll have runny eyes, too, sometimes not. If you notice sneezes, nasal discharge, or labored breathing, fluids SQ and steroids and such are usually what's given to get them over the hump. Sometimes they'll also have sores in their mouth.
Hoping she feels better soon.