Suggest Treatment For Fever , Cold And Cough In A Child

My 7 month old son has been placed on ampicillin for a rectal fever over 104, ear ache, and cough. He has been on it before without trouble. Yesterday, at the end of the 2nd day on it, he got a very light pinpoint rash on his trunk. He is also teething and had a fever for 3 days. I didn t know if I can continue the antibiotic or need to stop it?