I Was On Clarithromycin 500 Mg For 14 Days. Over

I was on clarithromycin 500 mg for 14 days. Over the last few days of the med and for the 4 days following I have started to have an uncomfortable itch on my upper back, chest & arms. I'm thinking the antibiotic should have left my body with 24hrs so I'm wondering want the chances are this is a drug reaction as opposed to something new developing.