It may be possible that you have developed a mouth ulcer
due the antibiotics given to you for ur infection.If its of recent onset then there isnt anything to worry about. Take multivitamin
tablets twice a day and eat plenty of fruits and vegetables. Despite this if the ulcer persist for more than a week then I would advise you to visit back the Dr who treated you to get a comprehensive check up. The ear pain
can be due to the same if the ulcer is in the back of the tongue and its supplied by the same nerve
as the ear.
I hope you found my response to be helpful and informative. If you have any additional concerns I would be happy to address them.