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It is more than likely that the female is already pregnant again as dwarf hamsters mate immediatly after birth. The new litter will be due in around seven days I think so you have plenty time to remove the male before he can mate agoin with her and you will have yet another lot on the way. This is very bad for the female as her body will become very run down. I am not sure what type your hamsters are. The look like either a black eyed white campbells and a normal campbells or a Pearl WW and a ?normal WW. I hope they are not one of each as hybrid breeding is not a good idea. They could both be hybrids also.
The baby looks well enough though and you should continue the good feeding with plenty protein. Once the male is removed you can sex the pup if you can. A female can stay with mum and a male can be introduced back to dad at around 4 weeks. Watch them carefully to be sure he accepts his son.