Are the wounds from mites, fighting etc?
What I would do is boil the kettle and leave it to cool. Then cover the surrounding fur with some tissue, and pour the cool water across the wounds. Don't touch the wounds with your hands or the tissues - just let the water go across the wound. It should remove any debris or dirt that's clinging to the area. If they're longhaired pigs, also consider trimming the hair back. If you do this, pour across some more water to remove the loose hairs. I'd be weary of doing much else yourself to be honest, you don't want to do more damage than harm. You can buy Tea Tree cream from a vet shop which is an antiseptic, it often has Aloe Vera added to soothe itching or inflamed skin.