A friend called her dentist about a reaction she's having on her face due to amoxicillin but the doctor said that she should continue taking the pills till she finishes. whatshould she do?

Medication Reaction: I am not sure about what "reaction" you are describing. Redness & swelling in area of tooth pain due to infection would be indication to continue taking medication. Edema unrelated to infection, rash, itching, or urticaria would all be indications of a potential allergic reaction & it would be wise to stop taking the offending medication, take some Diphenhydramine & monitor yourself closely.

Allergic reaction: Allergic reaction to medication will usually occur over the entire body, just not in the face. Your friend could have had another reaction to another product, like a cream or make-up or exposure to the sun. It is hard to say without seeing her or knowing the answer to these questions, and that is why it is difficult to second guess her dentist.

Dr's responsibility: These situations cannot be diagnosed over the internet. It usually needs to be seen unless the symptoms are clearly an indication of an allergic reaction which typically presents as red blotches, itching, hives, etc. We can't tell you or your friend what to do. It sounds like her dentist did not feel it was an allergic reaction based upon her description. This is the responsibility of the dds.