Fighting

hi everyone, i’m sorry if this violates any rules i just really need advice. i have two male dwarf hamsters, when i bought them they were caged together, so to my ignorance i housed them together when i got them. they were fine at first but now one has become more aggressive. i dont know if its territory issues or what, but i just got sent some pictures of one of them bloody. this is the worst it’s been and i dont know what to do other than get another cage? should i take him to the vet? it doesnt look too bad from the pictures but i know theyre small and can easily pass away, im just worried and need advice