My DD is also allergic to amox. She reacted with full body hives, and they were itchy. Pharmacist told me to stop the meds immediately, urgent care pedi told me to continue to give them to her!!

The child still had hives on her body even after Benadryl and steroids, and the pedi gave me instruction to dose her with Benadryl every 4 hours and sent us home with more steroids just in case.... but still said to finish the amox

We left there and I was 1,000,000x positive we would NOT be following that drs advice.
A call the next morning to her regular pedi confirmed my feelings on it- they said absolutely do NOT finish the meds, they treat just about any rash while on abx as an allergy. They switched out her abx to another one (that they said she could still react to, but that most kids don't) and she had no issues with that one.