Tumor? Vet costs.

[AwesomeSauce99]

Could somebody please help me?! My hamster Sugar is a Cambles dwarf and I have had her for 3 weeks now. She was fine for about a week after I got her. Happy,healthy, and very energetic. But then when I started to tame her i noticed an infection or tumor. I brought her to the vet and came home with antibiotics. They didn't work. I now suspect it is a tumor. She can't feel it ane its hard, crusty, black, and getting to be about the size of a large crumb. [IMG]20160901_231840.jpg[/IMG]
I have also noticed what appears to be a hole in her belly with might be discharge. She won't sit still for me to take a picture but should I be worried? How much would it cost for me to have it lasered? Is it a tumor? Please help my other hamsters died young of wet tail I don't want her to die too.

[souffle]

Where is the crusty black lump situated? This sounds like it may have been an infected bite from the pet store which is possible healed over now and scabbed? The image is not showing so hard to tell but these can take quite some time to fully heal over and can fill up with pus again then burst a few times.
I'm almost certain the thing on her belly is her scent gland. Is it about 'tummy button' position? The scent gland secretes a yellowy, sticky scent which can stain the belly quite heavily. The can also get infected but this usually happens in older hamsters. One thing to note is that the scent gland is much more prominent in male hamsters so you may have a male and not a female. Pet shops commonly mis- sex hamsters!
Try and get a pic but if you are really concerned you need to see a vet again and ask about costs as it is very hard to tell as it varies a lot around the world.