Thank you. I have a small blister type eruptions on my skin. I had surgery Tuesday for cervical spinal fusions and have a cervical collar to wear non-stop. I began to notice these eruptions Thursday morning in areas under the collar and then today, just a few minutes ago, I found some 2 behind my left knee. They are not painful...just itchy and bothersome. I am taking Percocet for pain management and wonder if the Percocet could be causing this problem.