Can i feed a leopard gecko milk?

my leopard gecko is over 18 years old and I haven't been able to get her to eat ANYTHING for over a month. I recently started giving her water with an eye dropper, so she won't dry up! Her tongue is not as pink as it used to be either. Anyway, was wondering if it would be harmful if I fed her MILK to give her some protein and fat in her diet? (Her tail is becoming the skinniest I've ever seen it)