With the wound, I personally wouldn't put cream on it as it will seal in any infection that might be present. If I were you, I would bathe it in salt water, and just let it heal itself. With it being on her mush, it will stay pretty clean anyway so long as food doesn't get into the wound as her saliva will clean it.

I don't know with regards to the growling, but it sounds like she is just telling you that she isn't comfortable with the situation.