Pimple size hard bump on neck of healthy 6 yr f no other symptoms she says it it tender when touched . should i worry about cancer?

Hard bump: I wouldn't worry about cancer but i would be concerned about an infection. Check with your doctor.

No, don't worry: Just keep an eye on it. A pimple-size hard bump in a six-year-old is very unlikely to be cancer, especially if it is tender. If it grows bigger or gets red or begins to drain, have a doctor see it. It's probably just an enlarged hair follicle or small cyst, and it will probably just go away on its own!