Help please.  I was in the sauna with a man, and he was showing off his penis while I was sitting there. At one point he asked me to grab it and masturbate him. I did it for a short while, twice (10 seconds or so, each time). Now I am concerned I may have caught something. We were in the sauna. He was sweaty. I did not see any sores or cuts on his penis, neither did I have any on my hands. Should I be concerned about any skin to skin stds? Please advise. Thanks!

Welcome back to the Forum.  Thanks for your continuing confidence in our service.  Masturbating your partner does not put you at any risk for any STI, including HIV.  That the encounter occurred in a sauna with heat and humidity does not change this.  FYI, the skin on the hands is particularly resistant to infection with any of the skin-to-skin STIs, even if your partner happened to have one.    I would have no concerns and see no need for testing.  EWH---

I do understand that gon, chy, and hiv are no worries, but what about skin to skin viruses and diseases? 

Even if the person had sores that I could not see and I did not?

As I said above, this was a no risk encounter.  Even in the unlikely circumstance that your partner had a cutaneous STI that you failed to notice, the skin of the hands is highly resistant to infection.  I would encourage you to not worry and feel that unprotected sex with your partner should be fine.  EWH---