Well there is a bit of a language barrier, but the vet told me, that it is probably a bacterial infection and that this makes her more vulnerable to lice, warts etc. We have no other animals in the house, so I guess there is slim chance of having fleas. And yes, I was asking her about antibiotics, but she said that there is no specific/focused treatment for this kind of bacterial infections. I don't know, I was kind of hoping for more specific results. I'm not sure if that thing was a wart or a byproduct of infection or a little bit of both.
I wrote to my friend, who has rats, if she ever got Stronghold for them. Some dogs have strange reactions to anti-flea medications, so I'm a bit worried about using them.
And I'm sure my hammie appreciates your comment about her wooden toys
. Thank you for saying that as well. I'm always a bit afraid that I'm doing something wrong, so it's good to have advice from someone with more experience.