My daughter has classic symptoms of dehydration. but now has a stiff neck severe headache but no fever. what could this mean?

ER or Doctor ASAP: headache and stiff neck raises possibility of meningitis. Even if it is unlikely, it is MANDATORY to have it excluded by a physician, either a pediatrician in an office or at the emergency room.

Needs evaluation: You should have her seen by a doctor as soon as possible. She has many of the symptoms of meningitis, and this is something you shouldn't wait on. Good luck!

Stuff necks: always get the attention of a pediatrician with a concern for meningitis. Although usually not the case, immediate evaluation in your doctor's office or emergency room is warranted.