Red urethra opening and several small bumps on penis head

[JuanPabloo]

Over a year ago I had unprotected sex.  Within weeks, I noticed very small "bumps" on the tip of my penis head, (reddish/purplish, painless and without pus, dimples, or wart-like appearance.)  I also became more itchy and  sensitive at the tip, especially around the hole and it became slightly red. Over the past year, more little bumps have appeared and the mild redness at the tip hasn't changed at all.  Since it is not painful, but rather irritating from time to time, I am not sure what it is.  I have looked at many pictures of STD symptoms, but none match.  I have shown it to three doctors, all of whom were unconcerned and said it is probably veins bursting....but I don't understand why they are, why the redness/discomfort persists, or what to do about it.  I am horribly depressed and scared about it.  I know something is wrong, but the doctors have failed to help.  I am truly desperate to solve this.  IF you can help me, please do.