Around 4 days ago, I had sex with a friend of mine, the next day, I noticed that around 6-7 small Pimple looking things were in a cluster around 2 and a half inches long and around an inch and a half wide, around 2 inches from my anus. I have never experienced anything like this before. The pimples are mildly itchy and not overlly sore but sore when i feel them. They look like regular pimples and i tried popping a few. Only one or two had any sort of pimple related substance come out, The rest, nothing came out. We did not have anal sex so i'm curious as to weather or not it was a coincidence that they appeared a day after sexual intercourse. They have become more sore since i have popped them and do not show any signs of subsiding any time soon. I have been putting monistat cream on them to sooth the itching. But i am concernced that this might be a sexually related infection. I was recently tested and everything came up negative and I have also read up on most common diseases that produce these symptoms and have looked at pictures and none of them fit the description. Another explanation could be ant bites because i recently discovered alot of ants crawling on my toilet seat. But do their bites last this long? I am really concerned and would appreciate someones opinion. I also didn't notice any skin irritations or anything abnormal about my friends genital area. Should I see a doctor? Oh and I am also on a form of contraception called 'Implanon' where a small rod is inserted into my arm and prevents eggs from being flushed during ovulation. Could this be a side effect of implanon?