About 4 days ago whilst on holiday I started noticing a slight discomfort in my scrotum and upon examining it i felt a small swelling around the region where the veins are for my left testicle, researched suggested it could be a varicosele as it is painless although I still notice discomfort/friction (not pain) whenever I'm active. I also noticed a strange kind of rash consisting of painless/flat red spots on the underside of my penis around the same time. The symptoms haven't worsened since I noticed them but I'm still quite worried about them. I've also had a few random small mouth ulcers over the past few days(not very big or sore but unusual). As for my history I did have unprotected sex twice with a girl around 3 months ago and even though I know and trust her, I am worried this could be some kind of potential std, any advice/similar stories would be appreciated, thanks