My guinea pig bites me when I hold him/her - he/she must not like me anymore. FALSE
If your guinea pig bites/nibbles on you, you may have trace sents of food on your hands/fingers and salts from sweat. Or simply that he/she no longer wishes to be held from a solid surface for long periods of time (be sure not to dangle their feet).
Try to wash your hands before you handle your
cavies and put them on your lap or a solid surface as soon as possible if they still bite/nibble while being held.
Also, some guinea pigs (like mine) may nibble on you to indicate their need to use the bathroom
inside of their cage, rather than go on their towel or blanket. Once they take care of business, they'll enjoy being held a lot more.