Herpengina or bacterial throat infection?

[Uae]

Dctr didn't tell me any diagnosis.. flu and strep infection is negative . But fever is still coming after every 4 hours .. I am giving him panadol and brufen alternately.. pkz help.. my 12 year old son have throat sore, fever ,headache, backache since 4 days

Initially dctr gave him augmentin than after 3 days ,dctr started cefixime but still he has fever.. his throat have ulcers ,do he have viral infection thts y antibiotic is not working? His throat ulcers look like harpengina but his fever is not going away,