I just bought a hamster and these welt like things appeared on my body. Only a few of them. They don't hurt and they don't itch. there about the size of a quarter. Here's a picture of them.
you could be allergic to the wood chips or some kind of natural oil on the wood chips i'd prob try washing it & being more careful about what you touch & such. you could also just be allergic to something else you use everyday sometimes when you are having chemical imbalance problems your body reacts badly to everyday things.
ya mostly its allergic eczema or atopic dermatitis, better take some anti histaminic like cetrizine and use some topical steroin ointment like becamethasone2%
They look like hives, but since you said there are only a few, they might be localized because of a scratch or bite.