Are these pimples new? Are there a lot of them clustered in one area? Are there shooting pains from them? It really is hard to say without seeing them what they are. It could be a number of things, or it could be just pimples. If they are new, and there are more than just a few, you should see a doctor. I had that happen to me once, and it turned out to be shingles, which needs to be treated by a doctor. There are other possibilities too, such as hives from an allergic reaction, etc. Best to play it safe and see your doctor.