hi bilb9494 it sounds a little similar to what i had, i slept with my (at the time) girlfriend and a day later i had these pimples with white tops on it came up. but also really bad sores around the area where my foreskin meets the head, the reason i had sores there was because we tried to have sex when she wasnt wet enough causing friction and a tear in the skin right a round the head (im not circumcised) But the pimples started off as one and in a couple of days had about 8 aswell but all in different areas. I went to the doc straight away and took a swob came back negative. I asked him what it could be and he said a yeast infection which could of caused them pimples. I spoke to a close mate about it and he has had the same thing once, he went to the doc and test came back all clears, the doc told him it was just sweat pimples. I have also had a blood test and came back all clear. But i still worry time to time when i see a little mark in that area. I hope this has helped but to be 100% sure go see you doctor and ask him.
You need to go and have this looked at by your provider.
grace