Hi,
I also hat this problem several times. I tried with antibiotic and it helped in half of the cases (infection will stay away for 12 weeks maximum). The only hamster that survived was Euridike, when I decided not to try with antibiotic before but get that thing out of her, as soon as possible.
( Looks like this one week after, Euridike was fit after 1 day:
We had several problems, but the cut was none.)
If the hamster is young and fit I wold do this again, but I would think about it, if the hamster is older. If you can buy enough time using antibiotic so that the hamster will die of something else earlier, this is fine, otherwise operation is the only way to give the hamster at least a chance...
Euridike has the problem that the little rest you cannot remove was infected. So have a look at this afterwards.
Good luck.