My sons hamster has developed a raw itchy patch behind his ear, I cant get a closer look because hes quite nasty and bites. I dont think it will be mites as we have no other pets and dont use hay (we use sawdust). So in the UK, how much do you think it will cost me to take him to the vet to be checked and treated? Thanks.
Instead of a trip to the vet, take a trip to the pet store. I'm sure you'll find a hamster that looks exactly like the one your son has. You might even end up with one that has a better temper.