A "normal" shed should come off all in one piece, if she got it off her head and it remains on the rest of the body, it's now considered a stuck shed. I suggest giving her a luke warm soak for about 10-20 minutes, then letting her run through a damp towel in your hands. Some people wet a pillowcase, or put a damp towel in a pillow case then let her wriggle through that to get it off herself, but I haven't done that method yet.

Also, here is a good thread on the shedding process. If you are using a lamp, it's more than likely the reason why she had a bad shed.