Cat attacked by another animal

My poor cat has been attacked by another animal! I have no idea what but it's on his face it has now become infected and I really don't have the money to take him to a vet is there anything I can use to help it ? Also his tail has big curled I don't know if that means anything his tail has never been curled up before I just find it a bit weird....

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I used hydrogen peroxide when my cat came home with a bite mark on his neck one time.  I just did a search to see if it is ok and it looks like there is better stuff but it looks like many people use it.  There is a discussion on this forum about it.  I even use it on my cat after I pull off ticks, I'll put it on a q-tip and then dab the area where the tick was.