Pigs are incredibly hardy as Carl says. We always keep a can of spray anticeptic for such occasions (ours sprays blue but I am sure other makes are other colours). It does for all of our animals - goats/sheep feet, pigs, cats and dogs - it is always a good one to keep in your first aid kit.
The worst wound we ever had here was when the goat butted one of our Tammies. It left a really deep very long cut - it looked appauling. No blood, it just went through the fat layer. The vet was called and apart from spraying it, said to leave it, it would heal on its own, and it did. You would never know anything had happened.
One of our piglets got stood on by its mum leaving a flap of skin and a nasty wound on its leg - again it was sprayed, we put a couple of disposable stitches in it and it healed beautifully - no scar.
They have very leathery noses, so don't worry too much. As Carl says just keep an eye on it but I am sure it will be ok and the tail is always a good sign of a happy or unhappy pig.
Kate