I have Fang back and equipped. I have walked all over Whisper Woods and have clicked on every dirt patch I could find. I am not finding the witchety grub. I also see in the walkthru it mentions that I would see purple lights from time to time that would lead me to these mounds when I have Fang equipped, but I don't see anything like that.
I have spent an awfully long time walking around looking. Can anyone help? I even went back to the End of the World to make sure I triggered that quest and to Ingrid's house to make sure I hadn't made the potion already and forgot to take it with me like the last potion I made.