I would advise different mantras for creativity. Erishkegal is a very important Goddess, but she is very much about pragmatism and doing tasks. Stripping down to the bare basics, no need for luxuries, doing what must be done. She helps through Neptune transits, gives a lot of grounding.
Based on Her attributes, I'm not sure where you heard Her name-mantra is for creativity. She is definitely a Goddess of Magick though. Creating magick, but not for artistic creativity if that's what you mean.