My Son Who Is 65 Lbs Has An Ear Infection

My son who is 65 lbs has an ear infection and it's very painful. I just got amoxicillin and gave him 5 ml about 6 hours ago. He is in extreme pain and I've been keeping up with ibuprofen. Can I give him a second dose of antibiotics to kick in the healing of the infection ? What are the risks? He's in extreme pain.