Throat infection after augmentin.

Hello, My daughter is 6 years old and wishes 22 kgs. She has had issues with her adenoids but has been ok for the last 6 months. 1 week back she had phlegm and cough and ear pain. Visited an ENT doctor who prescribed Augmentin for 5 days, twice a day. Her ear pain went away in 2 days and she felt better. Augmentin did cause a bit of throat ulcer which also resolved. Now after 3 days of stopping augmentin, she again has throat irritation, bit of phlegm and one  white patch on her tonsil. She clears her throat and coughs. We are making her gargle etc but between yest and today the redness in her throat has increased. Pl advice. We just finished antibiotics a week back and this is again there in 3 days. What could this be abd what would the next steps be please. I'm grateful for any advice. Thank you