My child has blisters on outer ear cartilage. this is the third day. she now has swollen lymph nodes and high heat in her neck?

This could be an of several viral infections: herpes simplex, herpes zoster (shingles), chickenpox if she hasn't been vaccinated, and others. Contact her pediatrician ASAP. Good luck.

Am acute infection including cellulitis should be considered. The blisters may require drainage and/ or a course of antibiotics. If this has recurred, an immune work up may be performed. Monitor temperature and see the Emergency room or urgent care. Please follow up.