4 y/o bit on the ear by another child. nurse said skin did not look broken. 3 days later, all redness gone but very tiny scratch need antibiotics?

Human bites: Ah, daycare. If it's been three days and the ear looks better, the ear should be fine and shouldn't need antibiotics . Human bites are concerning for infection, especially in ends of skin like the ear. Bacterial infection should have appeared by now. Let your pediatrician know and be sure that immunizations are up to date. (Helpful if not directly related).

Human bite: Just keep the wound clenched & dry, if it is red, swollen or oozing, then you need antibiotic ointment. Just make the kid that bit him is healthy with no contagious diseases. Good luck.