I just did a search on the internet, "how to unshrink woolen items", there were a number of sites that came up, one of them was:

1. Place the wool item in a sink full of warm water.
2. Soak for 10 minutes.
3. Remove the item and squeeze out excess water.
4. Let dry on a towel.
5. Carefully stretch and pull the item back to its original shape. Voila!

Good luck!

Laurin