Much to my great surprise, my Yoyo is still with me this morning, and has spent much of the morning sitting in the front of the glass closest to where I am sitting and watching me. When I got close to look at him he didn't swim away, just continued to look at me. He is perfect. He has a tiny indention at the base of his dorsal fin. Right in front of his ventral fins he has an abrasion on the left side, but it looks more like a small blood blister rather than being open and exposed. He is swimming around with the rest of the loaches and acting normally.
He is in the grow out tank with a mixture of young ones.
Yesterday -- my panic, his distress

This morning -- watching me.

A blurry look at the abbrasion. That's the extent of the damage I can see so far.
I love the coconut huts. I will make sure I buy the half in the future with no holes. I would buy them, rather than making them. I buy the reptile ones, instead of the hermit crab ones because they are $.50 cheaper. I boil it for half an hour, and I have had no problems. They add a little tannin, and they grow a carpet of algae and my fish and shrimp are constantly grazing the algae.