They are more commonly known as Grass Warts or Baby Warts and may be transmitted from the mare to the foal as the foal nurses. Young horses often catch them from each other, or they may pick up the virus from buckets, fences or any other place a curious young horse may stick its nose or brush against. They are most likely to affect horses less than a year and a half old, although George is now rising 5 years old.
Warts appear as small, grey/brown, irregular bumps. Most commonly seen on the nostrils and muzzle, they can also appear on any hairless or thinly haired area on the body, such as eyelids, or front legs. They can appear quite suddenly. There may be a few, or the whole area can appear almost encrusted with cauliflower-like bumps. If there is more than one young horse in a herd, they will probably have them at the same time.
There is no need to treat them. The virus runs its course and the warts drop off. It can take from 3 to 9 months, during which time they are unsightly, but harmless, unless you want to show or, as in George's case, break him in. This is not possible as he has them on his lips and the bit would interfere with them, make him sore and run the risk of secondary infection.
So, The training of George will have to wait until they have gone. Lucky George.