It sounds to me like fungal too, can you get us some pictures?

Oliver is alot better now, we have cream to put on him every night and although he protests i have managed to 2 it for the last 2 weeks and the gap is closing and pink skin growing around it, will continue with the cream and probably have to get another tube.

Like others have said I would say it was fungal especially if ivermectic didnt work after 3 injections and the other pig has not got any signs of the same thing.

Where are they kept, like room ?

If things are improving keep doing what you are doing but I would recommend if you are worried to post your problem on the Guinea Lynx website if you havent already as there are many very good experianced people on there who will be able to provide very indepth advice.

Good job on acting fast as you could, bad fungal infections can cause seizures and fits and even fatality if not treated so its a good thing you are taking action.

Just to add have you got any melts from Gorgeous Guineas website? They are good for fungal infections, atleast to make the piggy feel better anyway.