no, a bad shed will cause no serious harm. just a little bit uncomfortable for him. if you're using a tank with a screen top, take a towel and get it damp, and lay it over the top. you can also take a wash cloth or some paper towels, get them wet, ring them out, and put it under his hide so when he goes into his hide he's sitting on top of it and it creates a little "humid hide" until he's done shedding.