I would go to the vet. If it smells it is likely infected.

Could be an abscess draining pus. Can you see if there’s a sinus, a small hole where the pus is leaking out? Compresses of warm (but not hot) water will help to draw the pus to the suface to drain. But @JLeslie is right, you really need to see a vet in case gangrene or blood poisoning is taking place. Since it may not be painful (the nerves may be dead), your bunny will look healthy and happy even as it’s dying.

If he has an infection/abcess as ^ mentioned, and it sounds as if he does, topical treatment is not going to do it. He needs an antibiotic.
Do you have any feed stores in your area?
If so you can TRY ( no guarantees ) purchasing some powdered Terramycin and use about a teaspoon in his water bottle, changed daily, for several weeks.
Enough to turn the water a light to medium yellow color depending on the water bottles size.
Around a tablespoon to a quart of water.

This is a moderatety effective antibiotic used on rabbits, poultry, and bees, but really, he should be on Baytril or something much stronger if the infection is severe, and also if the wound has begun to fester he may have a staph infection which will require cleaning the dead tissues away along with the antibiotic.
Good luck, but the odds are not good that he will heal without some intervention.

Tea tree oil or even oregano oil might help.
Tea tree oil is good for skin and oregano has natural antibiotic properties. He may need more aggressive interventions though as others have said.

If the wound is enclosed and still swollen and full of puss then it’s an abscess and you have to open it and drain it. As others have mentioned, if it is an abscess topical preparations won’t help. A hot compress might work as @SmashTheState mentioned but I think it is best, if it is an abscess, to open it. You can use a small sewing needle to pierce the abscess and drain it. And personally, I wouldn’t bother with any herbal preparations. Hydrogen peroxide is very good for these things. I used to treat small abscesses that my cat got that way. Drain the abscess and treat the wound with a cotton ball soaked with peroxide several times a day. But you need to keep an eye on it. You can treat minor abscesses and infections yourself, with hydrogen peroxide but if the infection gets out of hand you will need to take the rabbit to the vet.

Rabbits are delicate creatures. I have found through vast experience that vet care is needed promptly for even small wounds.

This sounds like an abcess to me. Antibiotics are most likely a necessity in this case. (usually my rabbits have needed internal antibiotics for wounds/abcesses)

Are you certain there aren’t vets around? Even in the ruralest of areas there are vets traveling to farms.

Actually, maybe you should listen to @SpatzieLover rather than me. :-) I really have no experience with rabbits, just cats.

Mix up a paste of mashed onion, garlic and fresh ginger in an alcohol base and use it as a poultice on the wound. Replace every few hours. Onion and garlic are natural antibiotics, ginger plus the alcohol are antiseptic. It’ll sting the poor little mite, but probably less than the pain he’s already in from the wound. (I heard a countryman reccommend this concoction for an injured sheep many years ago).

Not to reiterate the good suggestions about draining abscesses and the like (which are all good BTW), I’d also like to add that if after draining it (if it is in fact an abscess), neosporin will help to keep the wound clean. My vet recommend it for my small dog on her cuts. I had a rabbit once too, but never had to deal with a cut. I will say one thing about rabbits – every once and a while feed them pineapple. My rabbit died of a massive hairball in its stomach. They need the acidity to break up the mass like that :(

@Ponderer983 @Bent Thank you.
@SpatzieLover @Judi @Coloma @SmashTheState @JLeslie
Thank you all for the prompt and informative responsive and for your concern.
As mentioned already, there are no vets, there is no car and quite surely there is no abcess, as there is no swelling. And, again I care to mention we’re not in the U.S. (but most of you surely already know this).
I have managed to find a local vet portal online and it gives apparently good suggestions as well.
We’ve continued this morning with the topical application of horse-tail tea dabbing.
Will try turmeric and now oregano. You see we have to use what we have NOW until we can be able to go to the towns.
Yes, it’s very backwood-like =O
I have alcohol. Don’t have fresh ginger and don’t have the antibiotics and no way of getting them as of now (But I think I will stock up on the Terramycin for eventual future cases). Although I did find an old medicinal I used for my puppies: Clorexyderm.
What do you lads & lassies think, should I use this?
Salut

Ah, by the way.. It just expire this January.
argh.

Use it anyway? :-)
In any case is it a good medicinal for small rabbits?

For future reference, honey makes a good antiseptic for a wound. It’s been used successfully this way for literally thousands of years and scientists have begun isolating the compounds which make make honey an effective antibiotic. And because honey is thick and sticky, it will fill holes like surgical packing.

Any news on how the bunny is doing?

Yes! he is well. The wound’s odour has reduced in intensity, at time to the point where it is appears to be absent. every morning and evening we’ve been giving him a dabbing session. Only two days ago a small swelling appeared but deflated the same evening, with some puss leaking. Now the wound is yellow and red right at the centre. It is dry and crusty all around, as it has been ‘till now with the only difference being that it now seems a bit harder.
Doing what we can.

@Anatelostaxus Yay! You never know. I once had a hen that was attacked by a raccoon or fox and she had, literally, a palm sized chunk bitten out from under her wing. I kept her in a box with a screened lid to keep out flies and kept the wound clean and salved in antibiotic ointment and it filled in and she was fine within a few weeks. Good news!