U wont hurt his feeling as long u asking him in a nice way,plus he did not stay by her cage 24/7 so anything can happen during the one week period time.could be anything as the all above posters mentioned....u will have to dig deeper even u dont have any money for the Vet right now,but the experience u learning is priceless.i really didnt want to because i dont want to hurt his feelings for making her sick but i will.
Why not ask ur friend or family to help u bring this sick cham to a vet,that will be the best thing to do right now asap.