What Causes White Spots Inspite Of Taking Penicillin?

Hi, i have been taking penicillin for strep throat for 7 days, the symptoms definately seem to be improving,headache gone etc! however the white spots are still there and its not quite healed. I work in a hospital and am due back in 2 days, should i wait until its completely healed? not sure if i would be putting patients at risk. It took me about a month with these symptoms before i went to the doctor, would i have caused any long term problems?