Probably only cosmetic?
I have a H-22. It had some surface cracks as well when I bought it. I think this is know as 'crazing'. On the topside, all I did was clean and paint with two part epoxy. It's a bit messy, but it sure looks good! Two coats in most areas, and I used my left over to give the cockpit more coats. One gallon did my entire topsides.