Can wool that has shrunk be unshrunk?

Sad to say, in my experience, once it has shrunk, you can stretch it a LITTLE bit, but I've never been able to make wool go back to its original size.

You can get some back, but water isn't going to do it. You need steam, the hotter the better. Apply steam liberally and then stretch it as much as possible. Then place on your form and stretch again. Find some way to hold it stretched and let cool, the longer the better. You can try this more than once, but most of what you will get will be from the first time. My Dad owned a dry cleaning plant and that is how we fixed shrinkage.

I don't know if this will help, but I've stretched baseball caps that were too small, to size. I used a plastic, reversible Bessey style clamp. (In reversed position, it spreads instead of clamps.) I wrapped each clamp jaw in a heavy rag/washcloth, then inserted the jaws into the hat, ratcheted it up to just-tight, then slowly increased the spread over the course of several days. Every once in awhile I'd stop and test so I wouldn't overstretch. Result was a custom fit.

Wonder what the result would be in combination with Larry's steam suggestion.

Felting is largely non-reversible.

Cheers