Give the antibiotics a chance to work. Don't think the worst, although as moms we all do bcuz it's our baby. I would call Ur regular pediatrician too & get her in to see her reg dr. My pediatrician says she's always changing what the hospitals ER does, wether it's a different prescription etc. I hope Ur little one is better soon.
I know hun i just can't help it. Definitely taking her to her regular dr for second opinion, just waiting for her to come back. Its scary as she never had a inflamed lymph node in that region before