Poor Fleki! He definitely should be seen by a vet. If you mean you are unable to take him to the vet due to cost, I suggest you call a local animal shelter, and ask them if they can assess him for you, or refer you to a vet who can.Here is a list of some shelters in Croatia
http://www.prijatelji-zivotinja.hr/index.en.php?id=1306 If you mean you can't get him to the vet because he's hard to travel with, visit the following site for more information on how to get him into a carrier
https://veterinarypartner.vin.com/default.aspx?pid=19239&id=5240362 Bite wounds are generally very painful, and can lead to infection if not treated. Fleki needs to see a vet so they can prescribe pain medication and antibiotics as needed. Pain medications meant for humans can be very dangerous (and even deadly) for cats, so I do not recommend giving any to Fleki without consulting a vet. One other very serious concern in a cat with bite wounds is the possibility of rabies infection, which is transmitted from the saliva of infected mammals, can be passed on to humans, and is fatal, making it even more important to make sure Fleki is seen by a vet. Having Fleki neutered and keeping him indoors can also help reduce the risk of injuries like this in the future. Good luck to you both and I hope he feels better soon!