Piggie scraching/hairloss

Question
My guinea pig has been scratching ALOT, and has bald spots all over his back.  Sometimes he even scratches himself so bad he bleeds alittle.  I tried changing his bedding, and hes still scratching.  What else could it be, and what can I do?

Another concern is he won't eat oranges at all!  What else can I give him as a source of vit. C?

Thanks, Vawn

Answer
it sounds like your guinea pig has mange mites and he needs to go to the vet asap for shots to help get rid of mange mites. The shots the vet should give the piggie are ivermectin. Here is a list that has other foods with vitamin C in it. http://www.guinealynx.info/diet_order-c.html