Hi, my young guinea pig has recently developed a sore on her back left paw. It has appeared on the top of her foot and takes the appearance of an open wound with pus rising from it. The rest of her paw is also swollen. We have been treating this by soaking her paw in a warm salt bath everyday and bandaging her foot straight after. I this a common guinea pig affliction? Is there anyway anyone would recommend treating it? We are not a high income family so taking her to the vet is a last resort and any other treatment would be preferable. Thanks.