Peeking into the rock

I have no idea what's good for a thumb, but in our area the Visiting Nurses Association for some reason has their very own hand clinic a person can get a referral to. I took Emma there when she was a young teenager showing signs of incipient repetitive motion injury and more than ten years later she has almost no problems though she uses her hands quite a lot. So I endorse what they do (pretty much the gamut of physical therapy modalities for hands).