
This afternoon I brought Dustin to the vet to get this small lump under his belly I detected Thursday looked at. So the vet felt the lump (and since it's on his lower belly Dustin promptly peed when pressed there), and unfortunately it's not clearly defined from the surrounding area. The vet suggested to treat it with spider venom before considering an operation, which is supposed to get the growth to become encapsulated in a more distinct shape or something like that, so that it can be removed more easily.
When I had rats before the vets never did anything like that, but the one where I'm now is quite experienced with rats, so hope this works as it is supposed to. I also asked whether the venom would tax Dustin's system further, since he still has the remaining effects from his respiratory problems and mycoplasma infection (i.e. that he's much less active than is brother etc.), but the vet assured me that it wouldn't have such negative effects. So now I have to bring him for at least two more injections over the next couple of days, and then the lump is going to be checked again, and will hopefully have a better shape for removal. There's apparently also a very small chance that it will respond so well to just the spider venom treatment alone that it shrinks and actually vanishes, but I don't expect that to happen, and it's not like Dustin has had much luck with his health in his life so far.
Anyway, the poor guy is sleeping now, stressed by both the vet visit and the heat which my rats dislike even under much more pleasant circumstances.