Making the assumption that you are assist feeding, what are you feeding and how often? 90 grams is pretty small. In my experience, its when you start putting some weight on them that they will finally turn on to eating on their own. I would probably try a fuzzy mouse every other day, always offering it first, and only assisting if it is refused. Every time I've tried this, the snake has started eating on its own within a week or two.

But like Joanna said, please provide more detailed information. Size and type enclosure, temps, heat source, humidity, hides, substrate, external surroundings (like is it sitting right next to your stereo speaker)....

Good luck!
Steve