Chocolate gourami has an issue

So I have this pair of chocolate gouramis. During water recycling one day, the smaller gourami got into the tube (blocked it off since) and got sucked into the bucket. He got some damage to the fins, but otherwise seemed fine. This happened like three weeks ago, but only now does he start showing a slowly growing white patch on his back. The tail and top fins don’t seem to have regrown either. I had tried esha 2000 when the patch was smaller, but mainly because another fish bumped into something and got a wound which I didn’t want to turn nasty.
The white patch seems to be a little bit deeper down than his brown skin, like a small piece of skin is missing

What can I do to get the chocolate better?

Bless lil fishy. Have you added anything to the tank? Or been doing daily water changes? Looks like scale damage but I’m not an expert.

It's a Fungal Infection;
1. Do 75% daily water changes and substrate clean.
2. Add salt; aquarium salt, pool salt or rock salt
3. Use Jungle Fungus Clear or any broad spectrum for fish.

If the Netherlands has the same policy as the UK, antibiotics won't be available without prescription. eSHa 2000 is the best medication, though you could try using salt - make sure it has no additives such as anti caking agents.

Chocolate gouramis are delicate fish, so maybe use 15 ml spoonful salt per 38 litres tank water.