See a rodent vet as soon as possible. http://www.rmca.org/Vets/ has a list of good rodent vets. The mulp can be a tumor or an abcess or something else, but only a vet can tell you what exactly and how to treat it.
It probably has a tumor.
You should definitely take it to the vet to check that out, hamster are very prone to cancer.
because he is a lump
belive me after a whil you will know the male will have huge balls that looks like a butt under its tail. and the female will not have this. the female will eventually have little nipples that the male will not have.
It is proabably a sore. Does it live with other hamsters? If not, you should definentally get it checked.
There are no home remedies for tumors, you should get your hamster checked by a vet.
it wqill have a lump on its butt
If it does not get better in a week or so then go to the doctor and have it checked out.
The Hampster needs expert medical treatment so you should take it to a vet.
Hamsters have little pads on their feet.
Look at their belly. If there is a black lump there, that is the male reproductive system, meaning the donkey is male. If there is no black lump, the donkey is a female.
Yes, that is the top of your rib cage.
The chest in front and the rump in the back.