There is a trick to it if it doesn't go away on its own.
Touch their head from behind and above. Not real hard. Just enough to get their attention. Since there's not enough room to bite they'll retreat. Follow their head with you hand until they are completely retracted. Hold your hand there a couple seconds and take it way. It basically force them the ball up and conditions them to ball instead of bite when their scared.
I learned that from Justin K. He even did a how to video on his Youtube channel.